Karen Armstrong: Exploring the common ground between the world's great religions

The author talks to Julie Wheelwright about behaviour and belief

As Karen Armstrong, the formidable historian of religion and a former Catholic nun, opens the door to her elegant 18th-century house in Islington, I am assaulted by a small dog. Armstrong is horrified by Poppy's behaviour and explains that she has just inherited the dog from her mother as she dashes off to organise cups of coffee while talking to her rambunctious charge.

Once seated, I ask her about The Great Transformation (Atlantic, £19.99), her new book on the so-called "Axial Age" of religious belief in the first millennium BC. This remarkable history traces the common conceptual themes that link thinkers and prophets such as Buddha, Socrates, Confucius and Jeremiah. The author of several best-selling biographies of religious figures and a history of fundamentalism, Armstrong says she wanted to explode the myths about the divisions between Islam, Judaism, Christianity, Hinduism and Buddhism. "I can't tell you how bored I get every time I step into a taxi and the driver says that religion is the cause of all the wars in the world."

After five years of painstaking research, Armstrong discovered that at the heart of the world's major religions lies the shared belief that compassion is the key to spiritual awareness. Reading in the British Library, she came across strikingly similar ideas that evolved in the Axial Age, from 900 to 200 BC, in four distinct regions of the world. "All the traditions that were developed during the Axial Age pushed forward the frontiers of human consciousness and discovered a transcendent dimension," she writes. It is not what you believe but how you act that leads to enlightenment.

"It goes right back to Buddha and Confucius," she explains. "It means action and not just wandering around handing out flowers and doing your own thing. It's a disciplined exercise of the Golden Rule." The emphasis on action rather than belief might sound straightforward, but Armstrong struggled for years to accept it. "I could not accommodate the idea in my head that religion did not have to be about believing things," she says. "I see this bafflement, especially when I talk to people here in the UK - people with very hard-line views about what religion is - when you tell them it's not about belief, but about behaving differently, that introduces you to transcendence."

Poppy momentarily interrupts the conversation by rummaging in my handbag and triumphantly pulling out a pair of new tights. As Armstrong dives for the dog she says wearily, "I love her but I'm the last person who should have a dog." Poppy spends a lot of time in kennels as Armstrong's travel schedule is head-spinning. Last week she was in Qatar and Egypt, where she is working on a United Nations initiative, The Alliance of Civilisations, with Archbishop Desmond Tutu. Next week she is off for an American tour to publicise The Great Transformation.

Armstrong has not just written a fascinating and highly readable history, but one which makes these ancient philosophies profoundly relevant. Her book, she says, "is a call for personal action and my study is my prayer; that's why I did it". There are modern resonances throughout the book, and when Armstrong was recently in Los Angeles recording an audio version, her producer interrupted her reading of the Daodejing, Laozi's classic of the "Way and Its Potency". "I was reading that bit where Laozi says, 'be victorious in battle but do not be triumphant, be victorious but do not gloat'. The producer suddenly beeped in and said, 'Boy, I was thinking of GW on that destroyer'."

A ripple of laughter follows Armstrong's imitation of her producer's Texan drawl, along with her wry understanding of why the deeply religious Bush should have The Great Transformation on his reading list. But unlike many British writers, she appreciates the American need to find a religious response to 11 September. "All fundamentalism is a riposte to a secular modernity whether it's Jewish orthodoxy, Christian, Buddhist, Hindu or Muslim," she says. "Every single fundamentalist movement has begun with an attempt to drag God from the sidelines to which he's been relegated in modern secular societies, back on to centre-stage."

In America, Armstrong has encountered religious people who feel colonised by what they perceive as the alien ethos of the Harvard-Yale-Washington secularist movement. "When people are afraid and are fighting with their backs to the wall, they lash out violently," she says. "In their rage and fear, they nearly always ruin the tradition they are trying to defend."

Armstrong's response to this crisis has been an increasing involvement in inter-faith movements. "The time has come to appreciate other traditions - it doesn't grab the headlines so much as the rhetoric of hate," she says. "There's a massive disquiet in the US about what's going on and a really strong desire to build new things with other traditions."

This life as a highly successful author who travels the globe to discuss religious belief and practice, however, was unimaginable to Armstrong when, aged 17, she entered a Catholic order as a novice nun in 1962. Although she left seven years later and spent several more "in recovery" as a student at Oxford reading English, she has never regretted the experience. "I couldn't have stayed," she says. "Very few people can live a life that's wholly celibate, wholly without material possessions and submit oneself wholly to a religious authority and become a mature person."

Neither does she regret the trauma of having her PhD failed, which effectively ruined her chances of an academic career. "I was an opinionated, bubbly girl and I got squashed in the convent, and I got squashed at Oxford, too, when I was in recovery from all of this."

Instead of becoming a lecturer at a minor British university, Armstrong taught at James Allen's School for Girls in south London and began to write. Her 1981 autobiography about life in the convent, Through the Narrow Gate, gained her a controversial reputation among English Catholics but proved that she could speak to a broader audience. Later, she became the presenter of celebrated documentary series, Genesis, and in 1993 wrote A History of God, which became a bestseller, then a book on Jerusalem and another on fundamentalism, The Battle for God.

"I am still a nun, really." Armstrong gently shrugs her shoulders, explaining: "Here I am living alone, writing about God and religion and spirituality. I'm an urban hermit." Although female theologians are still relatively rare, she shrinks at speaking on women's behalf. "I've been such a peculiar kind of woman," she says. "I've never married, I've not had children, I've never lived with anyone. The experiences which are crucial to the life and spirituality of the vast majority of women have been totally alien to me."

If she feels ill-at-ease as a representative female voice, Armstrong may be equally displaced in deeply secular Britain, where religious passion is regarded with suspicion or disdain. "Here even my own friends think I'm nuts to be wasting my time on this discredited stuff," she says.

In America things are very different, and Armstrong tells an anecdote that illustrates just how seriously religion is taken there. At a vast conference at the University of Oregon to discuss the state of God at the millennium, she spoke with six other theologians including Archbishop Tutu, a rabbi and an imam, to an audience of more than 1,500. Just as the delegates were listening to the conclusion that no one faith had a monopoly on truth, a protester, shaking with visceral rage, appeared in the auditorium.

"He said that Jews and Muslims had rejected Jesus and therefore they were going to hell, and all of us who were conniving in this process were going to hell." Armstrong pauses, searching for a way to convey the magnitude of the moment. "We were all absolutely hopeless. We seven who had done nothing but talk were struck dumb."

The apoplectic protester, wild with fear and rage, is Armstrong's metaphor for the greatest spiritual challenge of the new millennium. Although she has had to endure smear campaigns by the fundamentalists who have spread lies about her personal life, she believes they must be listened to and understood. "What is the alternative, with the world about to explode in hatred?" she asks. "If we want to save our planet, we need to go beyond our ideological camp. If we don't, we really are in grave danger."

Biography

Karen Armstrong was born in Worcestershire in 1944 and raised in Birmingham, where she attended a Catholic school. In 1962 she entered the Order of St Ignatius but left the convent to attend St Anne's College, Oxford. She was a research fellow at Bedford College before becoming head of English at James Allen's girls' school in Dulwich. She then wrote three television series, including Genesis for Channel 4. She is the author of 15 books including Holy War, biographies of Buddha and Mohammed, A History of God and two memoirs, Through the Narrow Gate and The Spiral Staircase. The Great Transformation is published next week. Karen Armstrong's books have been translated into 40 languages; she lives in Islington, north London.