Strange Fruit, by Kenan Malik

In one of his stories, the novelist Joseph Roth observes that it has come to be believed that every individual must now be a member of a particular race or nation. People have begun to think of themselves as Czechs, Hungarians, Romanians, Croats: each belongs to a group defined by the exclusion of others. A Jew from Galicia, until the end of the First World War part of the multinational Austro-Hungarian Empire, Roth viewed the spread of nationalism with foreboding. If the ramshackle Habsburg monarchy collapsed, he feared, the result would be xenophobia and ethnic mass murder.

By the time Roth's story appeared in the mid-1930s, the disaster had happened, though the worst was yet to come. Central and Eastern Europe was a morass of ethnic enmities, and in Germany the Nazis were implementing their poisonous mix of nationalism and racism. Was this just a detour in the onward march to a brave new world where everyone will be treated equally? Or did it – as Roth suspected – reveal a darker side of modernity? There can be no doubt about Kenan Malik's view. A pious disciple of the Enlightenment, though not untroubled by the doubts that can afflict any believer, he cannot tolerate the thought that some of the last century's worst atrocities were by-products of modern Enlightenment thinking.

Supposedly a study of the role of ideas of race in science and politics, Strange Fruit: why both sides are wrong in the race debate devotes only a few pages to Nazism and, aside from a brief discussion of JG Herder, the late 18th- century German philosopher of the Volk, barely mentions nationalism. These omissions are symptomatic.

Nationalism is a modern doctrine closely linked with liberal ideals of self-government, while Nazism – though it drew on some strands of Counter-Enlightenment thought and mobilised the prejudices of Christian anti-Semitism – was able to make use of a tradition of "scientific racism" that belongs squarely within the Enlightenment. The darkness that settled on Europe between the wars was not a reversion to medievalism. In crucial respects, it was peculiarly modern.

Malik admits that racist theories of the sort that came to power with the Nazis had some contact with Enlightenment traditions: 19th-century racial theorists, "for all their disdain of universalist ideas... maintained a belief in the idea of reason as a weapon of social transformation and social progress as the companion of a teleological history". A belief in science and progress is part of the Enlightenment creed. So why does Malik resist the conclusion that these racists were, despite the ersatz character of their so-called science, Enlightenment thinkers?

The answer is that Malik is not greatly interested in the history of ideas. His overriding concern is with current controversies about multiculturalism and relativism. A remnant of the old Marxist left, Malik is horrified by the way liberal opinion has embraced cultural difference. He has a point. Multiculturalism - the notion that society and public policies should be organised around cultural groups with different histories and identities – was a thoroughly silly idea.

The multicultural character of modern societies is a fact. Nearly all of us belong in a number of communities and traditions. But for that very reason it makes no sense to try to organise society on the premise that each person belongs in only one group. The real issue is how we are to live together, and learn to accept our differences.

Beginning and ending with an examination of the biologist James Watson's reported remarks about racial differences in intelligence, Strange Fruit is more of a topical polemic than a historical analysis. Malik contends that liberal anti-racists are as guilty of elevating race into the centre of politics as reactionary racial scientists. As he puts it, "Out of the withered seeds of racial science have flowered the politics of identity." Here Malik is half-right. Race is not a scientific category, and to the extent that it has been reformulated in cultural terms, the result has been a more fractious type of politics.

There is nothing new in this. Racism and the political assertion of cultural differences are features of the modern era. In earlier times wars were fought over religion and resources, as they are today. With the rise of doctrines of national self-determination, they began to be fought on culture and identity. When Roth mourned the demise of the Habsburgs, communists and liberals ridiculed his attachment to a pre-modern imperial structure. Yet it was Roth, not the progressive thinkers of the day, who foresaw the horrors that would come from its collapse. There is a lesson here, but it is not one that Malik - for whom progress and modernity are articles of secular faith - can be expected to learn.

John Gray's latest book is 'Black Mass' (Penguin)