There are only two kinds of music: good and bad.

Those who deliver this truism are usually considered to be expressing the ultimate in tolerance and pluralism. But is this appearance deceptive? Replace the word ‘music’ with ‘people’, and the formulation begins to acquire slightly less positive connotations, perhaps reminiscent of G.W. Bush’s ill-omened division of the world into axes of good and evil.

In everyday life we generally agree that there are many kinds of people of different temperament, pigmentation, background and orientation, and that between ‘good’ and ‘bad’ there are innumerable nuances that give our world its complexity, richness and, indeed, whatever beauty it possesses.

The superficial intention...