Like the attacks on Madrid, Washington and New York, the London terrorist bombings have brought an unlikely group of killers to the fore. These men appear to have been educated in Europe and assimilated within its liberal societies. Most lacked formal religious training, and none had experienced the oppression that supposedly drove them to such violent revenge.

How did these unexceptionable ­Britons, who were keen sportsmen, ­doting fathers or the sensitive guides of disabled children, become killers for an Islamic cause? The same question may be asked about their predecessors in Spain and America who frequented bars, visited nightclubs and gambled at casinos in another version of the ­ordinary life.

Unlike the members of religious cults or fringe political groups, few of these killers displayed signs of entering some closed ideological world by cutting themselves off from their families or everyday life. This suggests that the Islam they sought to defend was not conceived as an ideology at all since it did not provide a complete or ­alternative vision of the world into which the would-be bomber could retreat as into a fortress. Indeed, the kind of jihad retailed by al-Qaeda is remarkable because it is so open, ­lacking a coherent ideology or even a vision for the future.

The religion al-Qaeda follows possesses no established tradition, being made up of fragments snatched from discordant Islamic authorities. There are, at most, very general patterns of thought that are neither codified nor propagated in any systematic way. Rather than being recruited to a well-defined movement, the jihad's disparate soldiers franchise al-Qaeda's expertise and brand name for a variety of equally disparate causes that exist comfortably within the structures of everyday life. It is too complex a war to have been contained by absurdly simple expedients like not invading Iraq.

In many ways these holy warriors resemble the members of more familiar global networks, such as those for the environment or against war and globalisation. This is a world whose concerns are global in dimension and so resistant to old-fashioned political solutions, calling instead for spectacular gestures that are ethical in nature. ­Suicide bombing, for instance, is the most individualistic of practices. It is also an ethical gesture that participates only indirectly, if at all, in a solution to the problem it advertises.

Like the gestures that mark the environmentalist or anti-war movements, those of the jihad arise from the luxury of moral choice. The passion of the holy warrior emerges from the same source as that of the anti-war protester - not from a personal experience of oppression but from observing the oppression of others. These impersonal and even vicarious passions draw upon pity for their strength. And pity is perhaps the most violent passion of all because it is selfless enough to tolerate monstrous sacrifices.

Of course, al-Qaeda cannot be confused with Greenpeace, and suicide bombing is not the same kind of ethical gesture as protesting at Gleneagles. Yet it bears repeating that all of these movements, individuals and actions inhabit the same world, for if the London attacks demonstrate anything, it is that the British-born men who perpetrated them did not live in some hermetically sealed world of their own. Rather, they inhabited a thoroughly ordinary and unremarkable world in which such global issues as climate change, weapons of mass destruction and deforestation jostled with others

such as the oppression of Muslims, each beyond the reach of traditional political forms. This new world of global issues and networks emerged from the ruins of the cold war, which is why we are threatened today not with a revolution, ideology or state but by a practice of ethics that has arisen in the absence of global political forms.

Such a threat resists political containment and is unaffected by purely political attempts either to combat or engage it. For if total surveillance is impossible, attempts to address al-Qaeda's grievances are also doomed. Who is to be addressed and how? Will a retreat from Iraq suffice, or is the ­elimination of Israel also required?

Even the promotion of Islamic liberalism, itself a project dating from the 19th century, enjoys bleak prospects. Muslim moderates have had little ­success in their 150 years of existence, during which they have barely altered their plans of action, which include the reinterpretation of the Koran and

the dissemination of virtue through educational institutions. Al-Qaeda's jihad is not defined by the interpretation of the Koran, and the dissemination of virtue through education is itself a dream of the 19th-century state. Beyond the devices of counter­terrorism, then, Muslim militancy will probably only be transformed internally. In the meantime we must have the courage to wait it out.

The writer, assistant professor of history at New School University, New York, is author of Landscapes of the Jihad (Hurst & Co)