I sometimes smile wryly when I hear myself described as an "ex-nun". It is true that I no longer observe the vows of poverty, chastity and obedience that governed my seven years in a Roman Catholic convent during the 1960s. I am no longer poor, and am certainly not obedient. But I have never married, I continue to live alone, pass my days in a silence that would not disgrace the strictest cloister, and spend my life writing, thinking and talking about God and spirituality.
Being solitary holds no terrors for me. Unless one relishes long hours alone, it is probably impossible to be a writer. Somebody once called me a "gregarious loner". I thoroughly enjoy company, but become tense and feel depleted if I do not have an extensive period of time by myself each day. I also love my work. I can hardly wait to get to my desk in the morning, and when I enter a library, knowing that I can spend hours there beyond the reach of fax and phones, I can scarcely believe my luck.
So what follows is by no means a complaint. I do not repine at my lot and cannot imagine how I would have acted differently. For example, I had always assumed that, one day, I would find somebody to love and would get married like everybody else. Nearly all the other former nuns I know found spouses very soon after leaving the convent, but I have been singularly unsuccessful with men. Yet I also realise that, had I had a normal family life and responsibilities, I would not have written as much. Perhaps to succeed as a writer, it has been necessary - for me - to fail as a woman.
I had come to believe that this bias towards solitude sprang from a mental or physical flaw in my own nature; but I was intrigued by a recent article in the New York Times, which stated that a remarkably high percentage of academic women take out lonely-heart advertisements to find a partner, and that many have spoken of the loneliness that plagues their lives. In the universities of the United States, they claimed, women are almost invisible, so marginalised are they by the establishment. They feel excluded from the networking, bonding and promotional ploys used by their male colleagues. Is it possible that the kind of isolation I have experienced is an occupational hazard for the female intellectual?
As a freelance, I have not been subject to the institutional discrimination described by the American women. Nor have I felt excluded from the male epicentre at conferences. On the contrary, I have been moved by the generosity with which I have been welcomed by other academics and broadcasters.
In embracing the intellectual life, I seem, like those American women, unwittingly to have entered another cloister. Like nuns, academic women are often characterised as sexless, dowdy, humourless and frigid. The nature of our work also entails a withdrawal from the world. Whereas other clever women in the more sociable professions , such as law or publishing, can, if they wish, cultivate those nurturing qualities that make women beloved, academics and writers have to live a good deal inside their own heads.
The immense effort of dragging a book out of oneself demands a concentration that makes it very difficult to either reach out or to focus on the external world. For months, the outside world retreats and the real drama is enacted in the author's head.
Now, in a man, this degree of abstraction is usually regarded as noble and inspiring; but, in a woman, it is often condemned as selfish. It seems that such a degree of concentration is too far removed from the caring and sharing ethos popularly associated with the female. Women as well as men take me to task for appearing unfriendly, impenetrable and inaccessible when producing a new book, just as others scold me for remaining single, even though I have had no choice in the matter. The implication is that my lifestyle carries with it a degree of reprehensible solipsism that is profoundly unattractive. Perhaps this should not surprise us.
When women first gained access to the universities of Oxford and Cambridge in the late 19th century, they were stigmatised as flying in the face of their womanhood. Eminent doctors warned parents that their daughters ran the risk of a nervous breakdown if they attempted a mental exertion that was beyond their natural female powers. Almost every day, Emily Davis, the founder of Girton College, received letters from total strangers expressing their "repugnance" at the idea of "the competition between the sexes". Girls were neurologically different, wrote one correspondent, "their brains are light, their foreheads too small, their reasoning powers too defective, their emotions too easily worked upon to make good students".
It was generally agreed that women had been created for the domestic sphere. Academic study would make them "too strong-minded". How could they be "good sisters, wives, mothers and nurses"? How could a man marry a woman who was better educated than himself? Even the leading specialist Henry Maudsley argued, in 1874, that "study is the cause of ill health in women".
The first female intellectuals, who had to battle against such widespread prejudice, may well have been a trifle grim, and would have had to reconcile themselves to most of the men they met finding them repellent. Times have changed, and few would hold such draconian views today, but emotional attitudes live on in residual form, long after the official orthodoxy has been superseded.
The vision of the female scholar as unsexual, unattractive, unwomanly and unnatural still surfaces in unexpected quarters. Some men no longer find a woman's absorption in her work a personal affront; and some female intellectuals clearly have found no difficulty in integrating academic or creative commitment with personal satisfaction. But others, like myself, find that we are caught in a stage of transition, enclosed in a secular convent that has its own peculiar joys, but which excludes us from many mundane pleasures.
The Battle for God: fundamentalism in Judaism, Christianity and Islam by Karen Armstrong is published by HarperCollins, £19.99