She has not seen her sister in twelve years, not since their mother's funeral that rainy day in Melbourne. That sister, whom she continues to think of as Blanche but whose public name has for so long been Sister Bridget that she must by now think of herself as a Bridget, has moved – for good, it seems – to Africa, following a vocation. Trained as a classical scholar, retrained as a medical missionary, she has risen to be administrator of a hospital of no mean size in rural Zululand. Since Aids swept over the region, she has concentrated the energies of the Hospital of the Blessed Mary on the Hill, Marianhill, more and more on the plight of children born infected. Two years ago Blanche wrote a book, Living for Hope, about the work of Marianhill. Unexpectedly the book caught on. She did a lecture tour of Canada and the United States, publicizing the work of the Order, raising money; she was featured in Newsweek. So, having given up an academic career for a life of obscure toil, Blanche is suddenly famous, famous enough, now, to be having an honorary degree conferred on her by a university in her adopted country.

It is for that degree, for the ceremony of its conferral, that she herself, Elizabeth, Blanche's younger sister, has come to a land she does not know and has never particularly wanted to know, to this ugly city (she flew in only hours ago, saw it spread out below her with its acres of scarred earth, its vast sterile mine dumps). She is here, and she is tired to the bone. Hours of her life lost in the passage over the Indian Ocean; futile to believe she will ever recover them. She ought to take a nap, perk herself up, recover her humour, before she encounters Blanche; but she is too restless, too disoriented, too – she feels it obscurely – unwell. Is it something she picked up on the plane? To fall sick among strangers: what misery! She prays she is wrong.

They have installed the two of them at the same hotel, Sister Bridget Costello and Ms Elizabeth Costello. When the arrangements were made, it was enquired whether they would prefer single rooms or a shared suite. Single rooms, she said; and she would guess Blanche said likewise. She and Blanche were never truly close; she has no wish, now that they have passed beyond being women of a certain age to being, frankly, old women, to have to listen in on Blanche's bedtime prayers or see what fashion of underwear the Sisters of the Marian Order go in for.

She unpacks, fusses around, switches on the television, switches it off again. Somehow or other, in the middle of all of this, she falls asleep, flat on her back, shoes and all. She is woken by the telephone. Blindly she gropes for the receiver. Where am I? she thinks. Who am I? ' Elizabeth?' says a voice. 'Is that you?'

They meet in the lounge of the hotel. She had thought there had been a relaxation in dress for the sisterhood. But if that is so, it has passed Blanche by. She wears the wimple, the plain white blouse, the grey skirt down to mid-calf, the stubby black shoes that were standard issue decades ago. Her face is seamed, the backs of her hands are mottled with brown; otherwise she has lasted well. The kind of woman, she thinks to herself, who lives to be ninety.

Scrawny is the word that unwillingly comes to mind: scrawny as a hen. As for what Blanche sees before her, as for what has become of the sister who remained in the world, she would rather not dwell on that.

They embrace, order tea. They exchange small talk. Blanche is an aunt, though she has never behaved like one, so she has to hear news of a nephew and niece whom she has rarely laid eyes on and who might as well be strangers. Even as they speak she, Elizabeth, is wondering: Is this what I came for – this brush of lip against cheek, this exchange of tired words, this gesture towards reviving a past almost dwindled away?

Familiarity. Family resemblance. Two old women in a foreign city, sipping tea, hiding their dismay at each other. Something there capable of being worked up, no doubt about that. Some kind of story skulking, inconspicuous as a mouse in a corner. But she is too tired, here and now, to grasp it, pin it down.

'At nine thirty' Blanche is saying.

'What?'

'Nine thirty. We are being fetched at nine thirty. Meet down here.' She sets down her cup. 'You look bushed, Elizabeth. Get some sleep. I have a talk to prepare. They've asked me to give a talk. Sing for my supper.'

'A talk?'

'An address. I am giving an address tomorrow, to the graduands. You will have to sit through it, I am afraid.'

She is seated, along with other eminent guests, in the front row. Years since she was last at a graduation ceremony. The end of an academic year: the summer heat as bad here in Africa as back home.

There are, if she is to guess from the block of black-garbed young people behind her, some two hundred degrees in the humanities to be handed out. But first it is the turn of Blanche, the sole honorary graduand. She is introduced to the assembly. Clad in the scarlet gown of a doctor, a teacher, she stands before them, hands clasped, while the university orator reads out the record of a life's achievements. Then she is led to the Chancellor's seat. She bends a knee, and the deed is done. Long applause. Sister Bridget Costello, Bride of Christ and Doctor of Letters, who by her life and works has restored lustre, for a while, to the name of missionary.

She takes her place at the lectern. Time for her to say her piece, Bridget, Blanche.

'Chancellor,' she says, 'respected members of the University:

'You honour me here this morning, and I gratefully acknowledge the honour, which I accept on behalf not of myself but of those scores of people who for the past half-century have dedicated their labour and their love to the children of Marianhill and through those little ones to Our Lord.

'The form in which you have chosen to honour us is the form you are most easy with, the award of an academic degree, specifically what you call a doctorate in litterae humaniores, humane letters or, more loosely, the humanities. At the risk of telling you things you know better than I, I would like to use this opportunity to say something about the humanities, about their history and their present situation; also something about humanity. What I have to say may be relevant, I humbly hope, to the situation in which you as servants of the humanities find yourself, in Africa but in the wider world too, namely an embattled situation.

'We must sometimes be cruel to be kind, so let me begin by reminding you that it was not the university that gave birth to what we today call the humanities but what, to be more historically accurate, I will henceforth call the studia humanitatis or humane studies, studies in man and the nature of man, as distinct from studia divinitatis, studies pertaining to the divine. The university did not give birth to humane studies, nor, when the university eventually accepted humane studies in its scholarly ambit, did it provide a particularly nurturing home to them. On the contrary, the university embraced humane studies only in an arid, narrowed form. That narrowed form was textual scholarship; the history of humane studies in the university from the fifteenth century onwards is so tightly bound up with the history of textual scholarship that they may as well be called the same thing.

'Since I do not have all morning (your Dean asked me to limit myself to fifteen minutes at the utmost – "at the utmost" are his own words), I will say what I want to say without the step-by-step reasoning and the historical evidence to which you, as a gathering of students and scholars, are entitled.

'Textual scholarship, I would want to say if I had more time, was the living breath of humane studies while humane studies were what we can properly call a movement in history, namely the humanist movement. But it did not take long for the living breath in textual scholarship to be snuffed out. The story of textual scholarship since then has been the story of one effort after another to resuscitate that life, in vain.

'The text for the sake of which textual scholarship was invented was the Bible. Textual scholars saw themselves as servants in the recovery of the true message of the Bible, specifically the true teaching of Jesus. The figure they employed to describe their work was the figure of rebirth or resurrection. The reader of the New Testament was to encounter face to face for the first time the risen, reborn Christ, Christus renascens, obscured no longer by a veil of scholastic gloss and commentary. It was with this goal in mind that scholars taught themselves first Greek, then Hebrew, then (later) other languages of the Near East. Textual scholarship meant, first, the recovery of the true text, then the true translation of that text; and true translation turned out to be inseparable from true interpretation, just as true interpretation turned out to be inseparable from true understanding of the cultural and historical matrix from which the text had emerged. That is how linguistic studies, literary studies (as studies in interpretation), cultural studies and historical studies – the studies that form the core of the so-called humanities – came to be bound up together.

'Why, you may justly ask, call this constellation of studies devoted to the recovery of the true word of the Lord studia humcmitatis? Asking this question will, it turns out, be much the same as asking, Why did the studia humanitatis come into flower only in the fifteenth century of our dispensation and not hundreds of years earlier?

'The answer has much to do with historical accident: with the decline and eventual sack of Constantinople and the flight of Byzantine men of learning to Italy. (Observing your Dean's fifteen-minute rule, I will pass over the living presence of Aristotle, Galen and other Greek philosophers in medieval Western Christendom, and the role of Arab Spain in transmitting their teachings.)

'Timeo Danaos et dona ferentes. The gifts brought by the men from the East were not only grammars of the Greek language but texts by authors from Greek antiquity. The linguistic command that was intended to be applied to the Greek New Testament could be perfected only by immersing oneself in these seductive pre-Christian texts. In no time, as one might expect, the study of these texts, later to be called the classics, had become an end in itself.

'More than that: the study of the texts of antiquity came to be justified not only on linguistic grounds but on philosophical grounds too. Jesus was sent to redeem mankind, the argument went. To redeem mankind from what? From an unredeemed state, of course. But what do we know of mankind in an unredeemed state? The only substantial record that covers all aspects of life is the record of antiquity. So to grasp the purpose behind the Incarnation – that is to say, to grasp the meaning of redemption – we must embark, through the classics, on studia humanitatis.