Definitions of what jazz is and isn't have increasingly begun to fill the air. If it has this, this and this it's jazz. If it has that, it isn't. Usually "that" means electricity. For if there's one thing that jazz has never really come to terms with, it was that day when the Beatles touched down in America, triggering the rock explosion of the Sixties.
The effect on jazz was profound. By the end of the decade it was pragmatically adopting the electronic instrumentation and rhythms of rock, yet while the first wave of jazz-rock produced exciting music by the likes of Miles Davis, Mike Nock, Jimi Hendrix, Tony Williams, John McLaughlin and Weather Report, it was later undone by the commercial excesses of those in the mid- and late 1970s. So the emergence of Wynton Marsalis in the early 1980s championing acoustic jazz was particularly timely.
Style magazines and Sunday supplements lionised Marsalis, a cynosure for a born-again jazz, a star whose artistry, unusually, came to play a secondary role to his image. His success encouraged record companies to sign similar wunderkinder, creating a bandwagon effect that had the welcome effect of focusing media attention on jazz and raising its public profile. Adopting Marsalis's visual signature of sartorial elegance and using the adopted voices of some of jazz's older and sometimes posthumous heroes, this new neo-conservative movement has represented a major area of recording activity in jazz.
In recent jazz histories, Marsalis has emerged as a figure around whom post-jazz-rock fusion (or post-1970s) developments have been constructed. Yet in the past, the figures who were claimed to codify the diatonic, chromatic, harmonically free and rock-influenced eras of jazz, a Louis Armstrong, a Charlie Parker, an Ornette Coleman and a Miles Davis, were figures who moved the music forward. Jazz has historically been expressed as an evolving whole, a work in progress, its real potential expressed as a flight from the status quo. Marsalis, championing a return to a tradition- centred synthesis of earlier styles was precisely the reverse of this. His was a flight "back" to the status quo.
Jazz may be many things, but it's not supposed to be boring. Beyond the renascent homogeneity of the neo- conservatives, the jazz underground has tended to pay scant regard to Marsalis, a prophet facing backwards. Taking what they can from the acoustic and electric heritage of jazz they are producing music that reflects their own time, and not the values of previous generations. Take the music of Dave Douglas, for example, the New York Downtown scene's trumpeter of choice and one of the most imaginative young musicians in jazz.
His latest album, Wandering Souls (Winter & Winter 910 042-2), is with just a guitar and drums, a group he calls his Tiny Bell Trio. A scrupulous eclectic who traffics only in surprises, Douglas combines an open-vista imagination that incorporates the sound of a rock guitar with old-fashioned polish to create a mix of percussive energy and pointillistic poetry.
A couple of years ago, the guitarist Pat Metheny observed that when he saw young musicians playing as if they hadn't heard a note of rock'n'roll, he wondered where they'd been. When rock brushed up against jazz it let loose a whole range of possibilities that need not submit to commercial exploitation. No matter how appealing it might be to dwell on the style of a Duke Ellington or a Miles Davis, the original recordings by these masters will always overwhelm imitation, however earnest. In contrast, it is musicians like Douglas who are setting the agenda for the future.
Stuart Nicholson is the author of `Jazz: the 1980s resurgence' (Da Capo Press, pounds 12.50)