In search of a lost God. Friedrich Nietzsche saw himself as an heir to the Enlightenment, a partisan of reason whose task was to cut philosophy free from its roots in religion. But his quest led ultimately to madness and unhappiness. John Gray on the life

Friedrich Nietzsche

Curtis Cate <em>Hutchinson, 689pp, £25</em>

ISBN 0091801621

Nietzsche retains the power to enchant. While academic philosophy has retreated to the dim margins of the public culture, this all-too-human prophet of our disturbed modernity continues to fascinate a wide spectrum of thinkers and writers. They are not drawn to him by his excursions into metaphysics or the theory of knowledge. Rather, Nietzsche's troubled meditations on truth - he oscillated between denying that it could ever be known and seeing it as the destroyer of humanity's most cherished illusions - were not so much contributions to epistemology as records of his search for a viable alternative to Christian belief. Similarly, when Nietzsche disinterred the "genealogy of morality" his aim was not to come up with a theory of ethics. It was to consider what became of morality once its support in religion was taken away. He understood, fearlessly, that with the passing of Christianity both the authority and the content of morality were bound to change.

If Nietzsche remains inexhaustibly fascinating, it is because he embodies, in an extreme form, the dilemmas of religious thinkers in a post-Christian age. The son of a Lutheran clergyman, he abandoned a precociously brilliant but intellectually stifling career as professor of classical philology at the University of Basel for life as a nomadic outsider. Wandering Europe in search of respite from his chronic ill-health (he was probably syphilitic), the devout atheist acquired a reputation as a kind of saint among residents of the modest boarding houses through which he passed. It was a shrewd perception. Nietzsche spent his life searching for an alternative to Christianity; when he failed to find one, he felt compelled to invent a mythology of his own. The result was an absurd concoction - Zarathustra and the Superman, the Will to Power and the Eternal Recurrence - that bore all the marks of his Christian upbringing. Nietzsche's principal achievement as a thinker lies in his contributions to moral psychology, in which - developing the introspective method of French moralists such as La Rochefoucauld and Chamfort - he analysed and unmasked the Christian virtues, showing them to be sublimations of other, often "immoral" passions. Yet this incomparable psychologist had little insight into himself. He seems not to have grasped that the peculiar aura of sanctity he left behind him in his restless wanderings was the unmistakable trace of an unbelieving Christian in search of the God he had lost.

This monumental study of Nietzsche has been much awaited, and there will be some who will question whether the wait was worthwhile. There have been many Nietzsche biographies in recent years, the best of them so good that it is not unreasonable to wonder whether we really need another. There is Rudiger Safranski's compendious and authoritative Nietzsche: a philosophical biography (Granta) and Lesley Chamberlain's subtly penetrating account of Nietzsche's breakdown, Nietzsche in Turin: the end of the future (Quartet); it might well be doubted that there is anything more to do. These doubts may be set aside. Although it will not replace the work of Safranski or Chamberlain, Cate's Friedrich Nietzsche succeeds, as no previous book has, in making sense of the thought without contriving at the same time to make it boring.

Cate declares from the start that his book is not meant for "professionals" - university professors and teachers of philosophy - and this is evident in its light, terse style, so different from the convoluted dullness that is obligatory in the academy nowadays. That is not to say professional philosophers will have nothing to learn from it. It is received wisdom among philosophers that writers such as Nietzsche are best understood by breaking down their thought into a number of discrete propositions and arguments. Of dubious value in the history of ideas, this conventional methodology is completely inept when applied to Nietzsche. If his writings abound in contradictions, it is not because he was unaware of them, but rather that, believing truth in many areas of philosophical inquiry to be inherently paradoxical, he had no interest in system-building. Nietzsche's was a highly mobile style of thinking struggling to break away from inherited moral and metaphysical beliefs. His natural mode of expression was the aphorism. To seek to turn these insights into the building blocks of a systematic philosophy is obtuse. Looking for the interests that run through the successive phases of his thinking is a more intelligent strategy, but it cannot be fruitful without extremely close attention to the details of the life.

One of the delights of this book is its delicate description of the minutiae of Nietzsche's daily routine. Writing of his time in Sils-Maria, where he rented a "resin-scented, pine-panelled" room above the Alpine village's only grocer's, Cate recounts how, after rising while the dawn sky was still grey, Nietzsche would spend each day walking until 11am. After a short break, he would walk again, for another two hours, through the nearby forest or to Lake Sils, jotting down his thoughts in a notebook as he went along. After a late lunch of beefsteak and an "unbelievable" quantity of fruit, he would set out again on an even longer walk - "dressed in a long and somewhat threadbare brown jacket, and armed as usual with notebook, pencil and a large grey-green parasol to shade his eyes" - that sometimes took him as far as a mountain glacier. "Returning 'home' between four and five o'clock, he would immediately get back to work, sustaining himself on biscuits, peasant bread, honey (sent from Naumburg), fruit and pots of tea he brewed for himself in the little upstairs 'dining room' next to his bedroom, until, worn out, he snuffed out his candle and went to bed around 11pm."

Nietzsche's monkish peregrinations serve as a clue in interpreting this unworldly thinker. He seems to have come closest to happiness when he was alone. Though he needed friends, and attracted several who remained loyal to him throughout his breakdown and subsequent decline, few, if any, of Nietzsche's human contacts were successful from his point of view. His vaunted psychological acumen did not spare him a humiliatingly comic entanglement with Lou Salome, a sharp-witted and wilful young poetess who proposed a menage a trois with one of Nietzsche's closest friends, or enable him to see through the mystagogic poses adopted by Richard Wagner and his wife Cosima to the grubby reality of their unscrupulous careerism. An ardent admirer of Voltaire, whose lucidity of thought and unabashed cynicism regarding ordinary human nature he praised inordinately, Nietzsche saw himself as an heir to the Enlightenment, a partisan of reason whose task was to cut philosophy loose from its roots in religion. In fact, the passionate religiosity that runs through Nietzsche's writings shows him to be closer in spirit to Pascal, one of Voltaire's great betes noires. The mix of Enlightenment rationalism and despairing, God-haunted scepticism in him worked to destabilise an already fragile personality. In his relations with other human beings, Nietzsche resembled no one so much as Prince Myshkin, the holy fool portrayed in Dostoevsky's novel The Idiot.

At the start of his book, Cate attacks "the naive notion that Nietzsche was viscerally anti-religious". It is a naivety that infects a field of thought far wider than Nietzsche scholarship. Nietzsche rejected his first mentor, Schopenhauer, claiming that the latter was too much influenced by Christianity. In truth, Schopenhauer turned his back on Christianity more decisively than Nietzsche ever did, and it was partly for this reason that Nietzsche was compelled to break with him. For Schopenhauer, deeply soaked in Indian philosophy, it was self-evident that - contrary to the secular version of the Christian belief in providence propagated by Hegel - history as a whole is without meaning. If there is such a thing as salvation, it lies outside time, and presupposes shedding the illusion of personal identity. For Nietzsche, as for anyone who retains the humanist faith bequeathed to the world by Christianity, this vision of human life was intolerable.

Like innumerable, less reflective humanists who came after him, Nietzsche wished to hold on to an essentially Christian view of the human subject while dropping the transcendental beliefs that alone support it. It was this impulse to salvage a religious conception of humankind, I believe, that animated Nietzsche's attempt to construct a new mythology. The task set by Nietzsche for his imaginary Superman was to confer meaning on history through a redemptive act of will. The sorry history of the species, lacking purpose or sense until a higher form of humanity came on to the scene, would then be redeemed. In truth, Nietzsche's mythology is no more than the Christian view of history stated in idiosyncratic terms, and a banal version of it underpins nearly all subsequent varieties of secular thought. The militant atheist who charmed the good burghers of Sils-Maria with his innocent sanctity left a contribution to our religious inheritance that remains unacknowledged to this day.

John Gray's next book, Al-Qaeda and What It Means To Be Modern, will be published by Faber and Faber in May