These cohorts were not there in his name, though. The author himself felt that the ending of Saddam's oppression weighed heavily in the balance. He gives his protagonist Henry Perowne similar views, and sends the neurosurgeon away from the march, across West London in his Mercedes. The marchers looked at power and sensed injustice; Saturday turns its back on them, because it believes power can live up to its responsibilities.
The plot's ignition-key is turned by a minor march-related collision, the consequences of which threaten far more than the bureaucratic purgatory of an insurance negotiation. Crises out of clear blue skies are, of course, the price a character is apt to pay for being in a McEwan novel. The new development is that since Enduring Love, Saturday's thematic predecessor, the world has been changed by the crisis that erupted from the clear blue New York skies on 11 September 2001.
That is why we now check the rolling news the way we check our watches. Among the novel's panoply of virtues is its acute and sensitive ear for the noise in the background of ordered urban life. Perowne's scrape couldn't have happened to a luckier fellow. He is furnished not only with the car, the sumptuous Fitzrovian house and the professional skills, but also with a family of all the talents. His daughter is a precocious award-winning poet, his son a talented guitarist, his wife a lawyer.
The perfection of his relationships - only ever and still as much as ever in love with his wife, sex the incandescent core of their marital planet; at unspoken ease with his teenage son and in a loving tussle of ideas with his daughter - suggests not just luck but moral superiority. He even gets over to Perivale in the afternoon to visit his senile mother, though it is "like taking flowers to a graveside".
The worst thing he does the whole day is to use the instant diagnosis he makes of the other driver, Baxter, to avoid a beating from the latter and his hangers-on. Perowne detects in Baxter's disjointed gaze and moods the signs of Huntington's Disease; knowledge shifts the balance of power. The book's defining feature is the neurological terminology, which puts whole passages into a kind of Anglo-Latin creole.
Knowledge here becomes ornament; the syllables are Perowne's poetry. And they are more than ornament too: in Darwin's words, which he finds himself echoing, "there is grandeur in this view of life".
It matters that what one is being dazzled with is medicine rather than science. Perowne's knowledge affords him insight into how "mere wet stuff can make this bright inward cinema of thought", but his job is not to dissect the other "brightly wrought illusion" of the self. His goal is to restore these illusions. Huntington's Disease presents a textbook example of catastrophe wrought by an identified genetic culprit, "a single bad idea lodged in every cell, on every chromosome four", which he sees beginning to undo the integrity of Baxter's self.
At the same time, he retains the conviction that goes with the sense of self: that we have choices and responsibilities. His profession is one in which the responsibility that accompanies status is at its heaviest and most explicit. Looking at the disordered urban lives so readily to hand in the streets around him, he is inclined to think that these are down to molecules too, secret codes that make a person unable to "earn a living, or resist another drink".
It's all down to luck, the blue-sky kind or the shuffle of the genetic deck. On the other side of the coin, it's not the Perownes' fault that they are so wonderful. Like a surgeon's patients, all deserve equally meticulous observation and humane treatment.
Freed thus of the suspicions about power and privilege that have impelled its extras onto the streets, Saturday lives up to its own standards throughout. Its author's scrupulous application of his talent merits real gratitude from its readers. Saturday is distinguished by an intense literary imagination that is fundamentally scientific in its vision and its criteria.
There is indeed grandeur in this view of life, matter giving rise to minds which create the modern wonders - music libraries that fit in pockets, the cavalcade of lights, head and tail, along the London highway - that Perowne beholds with proper awe. But there would be none without the bright illusion - we can call it that because we cannot really believe it an illusion - of moral choice.
Marek Kohn's `A Reason for Everything' is published by Faber & FaberReuse content