It's comforting to discover someone who shares your rage against a cultural trend the world thinks is wonderful. This happened to me the other day I was leafing through the London Review of Books, and came across a list of events taking place at the British Museum. Among them was a concert given by a mixed bunch of Indian and Western musicians - the kind of mish-mash that normally makes me pass by in a hurry. But what really struck me was the title: 'This is Not a Fusion'. Aha, I thought; there's someone out there who feels the way I do about fusion.

Being against musical fusion is a bit like being against globalisation. You appear faintly ridiculous, a kind of Canute holding up an impotent hand against the tidal wave of musical crossovers. And let's face it, it is a tidal wave. Forty years ago when someone brought a sitar into pop music, or used gamelan scales in a piano concerto, it was noteworthy. Now a mingling of global flavours has become practically the norm.

Why should this worry us? Haven't cultures always mingled and fused together since mankind has been on the planet? And isn't a plea for the alternative - a purity of musical cultures - a rather suspect and even slightly fascist idea? Indeed it is, but the idea of musical purity is an Aunt Sally, erected by the fans of fusion so they can feel morally superior by knocking it down. No one in their right mind would want to argue for the superiority of 'pure' musical cultures, for the very good reason there aren't any, and never have been.

But there's all the difference in the world between a genuine cultural fusion and a shotgun wedding - which is what today's musical fusions generally are. The two essential factors in a real cultural fusion are time and emotional ambivalence. Take the example of the gradual ingestion of the Arab lute, or 'ud into Western music. There must have been fascination at the first encounter, certainly. But there must have been a certain disgust, too, because the tuning of an Arab 'ud is wrong by Western standards. This 'wrongness' was bound up with the fact that these sounds weren't just sounds, they were the musical signature of the infidel, the threatening Other. Think what a slow coming-to-terms that must have entailed, before the 'ud could re-emerge in Europe as the lute!

These days there is no coming to terms, because the music industry, and the ideologues of multiculturalism, are in too much of a hurry. They want results now, so emotional ambiguity, and the time needed for real understanding, must be banished. Instead the elements in the 'fusion' have to be reduced to a quickly digestible parade of flavours: the mystical-erotic sitar, the melancholy Irish pipes, the innocently twee Chinese lute. These flavours are embedded in a basically Western harmonic framework which accentuates their picture-postcard prettiness.

On the face of it the British Museum concert doesn't seem so different, with its mix of Indian vocals and tabla with guitar and piano. But it was conceived and led by someone who is bound to be against fusion - the writer Amit Chaudhuri. He's known in Britain as a fine novelist and literary critic, but it turns out he's also a very accomplished singer in the classical Hindustani tradition. His novels deal with the difficulties of the cross-cultural lives lived by an increasing number of the world's peoples; not just the millions of refugees and emigrants, but the equally large numbers of people like himself who've been educated abroad. Returning home, they find their sensibilities have changed, and with that change there comes a confusion.