BOOK REVIEW / Into the modern world with the butterflies: 'Postmodernism, Reason and Religion' - Ernest Gellner: Routledge; 10.99 pounds

ERNEST GELLNER's new book is one half of what was originally intended to be a single jointly written volume. Akbar S Ahmed, Gellner's co-author, has also converted his work into a book in its own right (Postmodernism and Islam, Routledge, pounds 10.99). Gellner tells us that the publisher decided to publish the two books separately, and you can see why: they could hardly be more different.

God created two types of anthropologists. Those who collect butterflies and those who develop theories. Akbar Ahmed is a butterfly collector, Ernest Gellner is a theoretician par excellence. Their books illustrate the difference between an analytical mind at work and a mindless collection of anthropological and sociological facts.

Gellner offers a razor-sharp analysis of 'three fundamental and irreducible positions' on faith: religious fundamentalism, postmodernism and his own stance, which he calls 'rationalist fundamentalism'. Each position is carefully defined - postmodernism is pinned down as 'a kind of hysteria of subjectivity' - and dissected with a refreshing breath of knowledge and wisdom.

Gellner's concern is to rescue 'serious knowledge' from the postmodernist and fundamentalist strait-jacket of absolute subjectivity. His 'mild', common-sense rationalism combines reason with virtue and presents a sagacious intellectual position that most sensible Muslims would be happy to endorse.

In contrast, Ahmed offers a hodgepodge of half-related and unrelated facts united only by a keen preoccupation with the person of the author. We begin with a breathless list of television appearances, radio discussions, newspaper interviews and audiences with celebrities, and proceed to a rambling rap of postmodern phenomena gleaned from newspaper clippings and video magazines.

In between, we are repeatedly reminded that the author rubs shoulders with perennial greats such as Mick Jagger, the Aga Khan, Melvyn Bragg, Benazir Bhutto and Salman Rushdie; and that he makes frequent appearances on The Late Show.

It is almost impossible to discern what Ahmed is trying to say. But what he does demonstrate quite satisfactorily is that he has little understanding of what constitutes postmodernism, and has an equally superficial appreciation of the world view, history and culture of Islam; a point amply illustrated by his description of the old-fashioned territorial dispute over Kashmir between India and Pakistan as 'a model postmodern phenomenon']

The key insight of Ahmed's book is that Muslims, frustrated with modernity, are beginning to appreciate postmodernism because they are learning to laugh at themselves. In case you have difficulty identifying Muslims, Ahmed authoritatively informs us, they are the ones who 'insist on wearing robes' while jeans are 'universally popular in the West'.

Beyond this cuckoo analysis, Ahmed the butterfly collector cannot resist the temptation to classify his collection of facts. It looks as if all the Muslim scholars of the world live in Britain; and all Muslim journals are published from here. Thus, Ahmed can acquire his collection of Muslim writers sitting comfortably in his armchair in Cambridge. They are pigeon-holed as 'traditionalists', 'radicals' and 'modernists'.

Unhappily, even a simple classification needs some mental legwork. Ahmed, ignoring the thoughts of most Muslim writers, manages to produce some strange bedfellows. Thus Rana Kabbani, a committed Muslim, and Salman Rushdie, who has denounced Islam more than once, are both described as 'modernist Muslims'. The aggressively fundamentalist Kalim Siddiqui and the passive, anti-fundamentalist Parvez Manzoor are both described as 'radical Muslims'. The Sufi mystic Hossein Nasr and the late Fazlur Rahman, an assertively anti-mystic thinker, are both 'traditionalist Muslims'.

Gellner produces a much neater, conceptual classification of the 'high' Islam of scholars and 'low Islam' of the people. And neither of them, he shows, have anything to do with the real spirit of Islam.