What persuades men and women to mistake each other from time to time for gods or vermin is ideology. One can understand well enough how human beings may struggle and murder for good material reasons - reasons connected, for instance, with their physical survival. It is much harder to grasp how they may come to do so in the name of something as apparently abstract as ideas. Yet ideas are what men and women live by, and will occasionally die for.

The role of the intellectual, so it is said, is to speak truth to power. Noam Chomsky has dismissed this pious tag on two grounds. For one thing, power knows the truth already; it is just busy trying to conceal it. For another, it is not those in power who need the truth, but those they oppress.

The Kantian imperative to have the courage to think for oneself has involved a contemptuous disregard for the resources of tradition and an infantile view of authority as inherently oppressive.

The political currents that topped the global agenda in the late 20th century - revolutionary nationalism, feminism and ethnic struggle - place culture at their heart.

An enlightened trust in the sovereignty of human reason can be every bit as magical as the exploits of Merlin, and a faith in our capacity for limitless self-improvement just as much a wide-eyed superstition as a faith in leprechauns.

It is silly to call fat people "gravitationally challenged", a self-righteous fetishism of language which is no more than a symptom of political frustration.

The British are supposed to be particularly averse to intellectuals, a prejudice closely bound up with their dislike of foreigners. Indeed, one important source of this Anglo-Saxon distaste for highbrows and eggheads was the French revolution, which was seen as an attempt to reconstruct society on the basis of abstract rational principles.