In an essay on the writer Seán O'Faoláin, Conor Cruise O'Brien wrote about ideas of childhood and memory: "There is for all of us a twilight zone of time, stretching back for a generation or two before we were born, which never quite belongs to the rest of history. Our elders have talked their memories into our memories until we come to possess some sense of a continuity exceeding and traversing our own individual being … Children of small and vocal communities are likely to possess it to a high degree and, if they are imaginative, have the power of incorporating into their own lives a significant span of time before their individual births."

The twilight zone of time for me goes back decades before I was born. It is always Enniscorthy; and it belongs also to earlier generations of my family. When she died, my mother left me her books and her CDs. Her A Golden Treasury of Irish Verse, edited by Lennox Robinson, is dated in her handwriting: 27 January 1941. She would have been 19 then. At the back of the book are pasted two poems she wrote, which were published in the local newspaper, the Enniscorthy Echo, and then reprinted in the Dublin newspaper the Irish Press in 1941, with a commentary by one of the editors calling the first of them "lovely" and the second "exquisite". The two poems had been published with her initials only, but it was known in the town that she had written them, and it gave her a sort of fame among her friends.

It is something I was aware of as I grew up. I knew how much the poems mattered, as if I had somehow shared the experience myself of seeing them in print, or being around when they were written.

Between the pages of another anthology she owned is a cutting from the local paper with the news that a pageant my mother wrote in the mid-1960s won an all-Ireland competition run by the Irish Countrywomen's Association. I remember the pageant being performed; my mother could not go because my father was too sick. But I went. I think I was the only one of the family who ever saw it performed. It was in rhyming couplets and was recited by actresses representing the women who took part in the 1798 rebellion in Wexford. I can even remember one of the couplets: "This is about myself, Anne Flood / And how I spilled a Hessian's blood."

Later, when the Irish Times ran a weekly competition for light verse, my mother entered every week and won sometimes. I remember one of her end lines as it appeared in the paper: "When the Greeks bring gifts, who fears to get?"

It mattered to her that she could have, or might have, been a writer, and perhaps it mattered to me more than I fully understood. She watched my books appear with considerable interest, and wrote me an oddly formal letter about the style of each one, but she was, I knew, also uneasy about my novels. She found them too slow and sad and oddly personal. She was careful not to say too much about this, except once when she felt that I had described her and things which had happened to her too obviously and too openly. That time she said that she might indeed soon write her own book. She made a book sound like a weapon. Perhaps a book is a weapon; perhaps an unwritten book is an even more powerful weapon than one which has been published. It has a way of filling the air with its menace or its promise, the sweet art of what might have been.

Unwritten books and poems mattered to me when I was growing up; there was a melancholy sense of what was never achieved, and that sense has been vivid for me, and it still is, even more than some things I remember happening, or that I saw coming into being.

I dislike being called a storyteller, and resent the implication that I come from a world where the oral tradition, something primitive and unformed, remained strong or intact. This was not true; the oral tradition was not strong in the place where I grew up. I was brought up in a house where there was a great deal of silence. When my father died, his name was hardly ever mentioned again. It was too much that he had died, too hard; his absence was too palpable, too sad. So it entered the realm of what you thought about and did not speak of, a realm I remain very comfortable in to this day.

But sometimes in the years before my father died, he and his brother and sister talked of their other brother, Philip, who had died of tuberculosis in 1940. I know the date because I found his grave one day when I was looking for my father's grave, and I saw that he had died a very short time after his own father. This fact had never been mentioned at home, but they must have lived through those two deaths and then held them close. The deaths were significant enough not to be mentioned. When I imagined them and put them into my novel The Heather Blazing, the older members of the family were, I think, all shocked by those scenes I wrote, but they never talked about them, at least never to me. The book became another thing that the family could be silent about.

It was agreed as I was growing up that my uncle Philip who had died was the cleverest of all of them. He wrote poems too, in Irish and in English. A few years ago, I found a sheaf of them in the bottom of a drawer in that house in Enniscorthy where they all lived. He used more elaborate verse systems than my mother, the sister-in-law he never met; he managed a late-Victorian decorum in his version of Wexford pastoral. After he died, some of his poems were published in a cheaply produced literary magazine that both my parents worked on in the town.

Thus there was for me this twilight zone of time which is filled with the unspoken, the unwritten, what might have been done in a significant span of time before my own birth. It is a zone filled with promise and with failure, filled with the idea that there were two people, one on either side of the family, who could have become me, or someone like me. If my uncle had lived, they were all sure that he would have been a poet, or a writer of some sort; and my mother in later years would go over what happened to her, how she was taken out of school at 14 when her father died, and if this had not occurred she could have become educated, and she could, she knew, have done anything then. Poetry was merely a small part of it.

I listened carefully when they talked about the past, and I absorbed it and came to see it. Sometimes in dramatising a scene in a book or a story, I found myself in the rooms that these people – the one or two generations before mine – had been in, and was impelled, almost compelled, to conjure up what I knew must have happened, what was hardly ever mentioned but was half-known, half-understood. It was like working with ghosts rather than imagined characters, with dust and faded things as much as with words and sentences.

I remembered smiling to myself when I found an attack by WB Yeats on a group of politicians in Dublin. They were the sort of people, he said, "who do not have books in their houses". In an Irish context, it is hard to think of a greater insult, especially if it were directed at people who had any money at all. In my parents' house, and in the house of my uncles and aunts, there were books, and sometimes complaints that there were too many books. They had very little money, but the notion of having no books would have been impossible. The idea of the written word was not merely a luxury. Being literate meant that you could get a job, and the job would be indoors, and come with holidays and a pension. My father was a teacher, his brother a journalist, his sister worked for the local council in their offices. Even though my mother left school at 14, she and her two sisters worked in offices and prided themselves on their command of grammar and syntax and their beautiful handwriting. While reading and revering books and writing itself had a spiritual value, and were part of an unworldly set of ambitions, they also had practical consequences. They could lead to a university scholarship, or at least a good, secure job. They might mean that you would not have to emigrate.

This idea of the older generation as strange, insistent shadows moving closer and closer to substance as time went on, the idea that I was writing, pushing myself to work, almost because they could not or did not, that I was inspired by their silence, has echoes in the work of other writers. In the volume of letters between VS Naipaul and his father, for example, there are moments which I fully recognise, in which the shadow hovering over the son as he set out to become a writer was the shadow of failure, of someone who did not get the chance. In March 1951, when Naipaul was an undergraduate in Oxford, his father wrote to him from Trinidad: "I am beginning to believe I could have been a writer." A month later, Naipaul wrote to the family at home: "I hope Pa does write, even five hundred words a day. He should begin a novel. He should realise that the society of the West Indies is a very interesting one – one of phoney sophistication."

Soon, his father wrote to say that he had, in fact, begun to write 500 words a day. "Let me see how the resolve works out," he wrote. "Even now I have not settled the question whether I should work on an autobiographical novel, or whether I should exhume Gurudeva." In 1943 he had privately published Gurudeva and Other Indian Tales in Port of Spain. But it would be his only book; he died in 1953 at the age of 47.

Reading the letters between the father and the son, and coming suddenly on the stark news from home that the father has died and that it is now up to the son alone to write the books, gives us a sense of the origins of Naipaul's extraordinary industry and seriousness as a writer, the slow, careful rhythms of his prose, the painstaking care with which he constructs his sentences. These were luxuries not allowed to those who came before him. There were ghosts in the room when he worked.

Jorge Guillermo Borges, the father of Jorge Luis Borges, also published a work of fiction privately. In Majorca in 1919, as the son was writing his first poems, the father was working on his novel, which came out two years later when he was 47 and his son 22. In 1938, as his health was failing, Borges senior suggested that his son might consider rewriting his book, making clear that they both had discussed the novel as it was being composed. "I put many metaphors in to please you," he told his son, asking him to "rewrite the novel in a straightforward way, with all the fine writing and purple passages left out".

Borges's late story "The Congress" may be, indeed, a retelling of his father's novel, just as Naipaul would retell a version of his father's life in A House for Mr Biswas. Borges's biographer Edwin Williamson emphasises that Borges set out in his story not to mirror his father's fiction as much as "to transcend it". Williamson goes on: "The basic structure and plot of the two works are identical: there is a powerful chieftain poised between civilisation and barbarism." But Borges knew that his work would find readers, that he would not have to ask anyone to rewrite it, and would not have to publish it himself.

Thus the death of Borges's father and Naipaul's father left space clear for the sons to work. They would only have powerful ghosts rather than real presences looking over their shoulders, ghosts whom they could dismiss at will. Like Picasso, whose father was a failed painter, or William James, whose father was a failed essayist, they could compensate for their fathers' failure, while killing off the fathers' indolent influence. They could show their mother, or indeed the world, who was the real man in the household.

This idea of the death of the father, and the father's failure, as a sort of liberation is considered by Richard Ellmann in his book Yeats: The Man and the Masks. He quotes Ivan Karamazov – "Who doesn't desire his father's death?" – and then writes: "From the Urals to Donegal the theme recurs, in Turgenev, in Samuel Butler, in Gosse. It is especially prominent in Ireland. George Moore in his Confessions of a Young Man blatantly proclaims his sense of liberation and relief when his father died. JM Synge makes an attempted parricide the theme of his Playboy of the Western World. James Joyce describes in Ulysses how Stephen Dedalus, disowning his own parent, searches for another father … Yeats, after handling the subject in an unpublished play written in 1884, returns to it in 1892 in a poem 'The Death of Cuchulain', turns the same story into a play in 1903, makes two translations of Oedipus Rex, the first in 1912, the second in 1927, and writes another play, Purgatory, involving parricide shortly before his death."

The idea of a writer using art as a way of seeking power within a family arises in any consideration of the Yeats family. In the summer of 2004, I began to look through the family's letters, which are housed in the library of Union College in Schenectady in upstate New York. I already knew the published letters of John Butler Yeats as among the most eloquent letters ever written, with a freshness in the thought and a startling originality in the phrasing. I also knew some of the old man's work as a painter and was aware that he laboured for many years on a self-portrait which he continually erased and began again. He was a great talker and much loved by his friends, but he was also indolent and useless at making money. He was not good at finishing things and produced two sons, the poet WB Yeats and the painter Jack B Yeats, who were known, on the other hand, for their lifelong industry and their ability to offer a ringing sense of completion to anything they began.

As I browsed through the letters, I noticed the brilliant wit of Lily Yeats, the older of WB Yeats's two sisters, and how close it was to the style and tone of Alice James, the sister of William and Henry James. If these families produced two geniuses, there was something in their dynamic that served to crush a number of the other siblings, no matter how clever they were. Lula and Carla Mann, the sisters of Thomas and Heinrich Mann, for example, both killed themselves. The youngest of the Manns, Viktor, produced one pathetic book called We Were Five. His title, once you begin to study these families, seemed as much a cry for help as a statement of fact.

I found the letters from John Butler Yeats, written to his son from New York, from the great unfinisher to the connoisseur of completion. He was, it was said, one of the few fathers who lived long enough to be influenced by his son; to avoid this influence, or lessen its power, he moved to New York in 1907 at the age of 68 and refused to come home. He died there in 1922. During his long and carefree exile, he was bankrolled by his son the poet. In 1918, as WB Yeats arranged with the New York lawyer and collector that in exchange for financial support for his father he would hand over manuscripts and drafts of poems, he wrote: "I hear with some alarm that he is writing a play, in which, as it is the most highly technical of all literary forms, he will most certainly not succeed."

In his letters to his son, John Butler Yeats makes many references to his own writing. As I went through the letters written over the 20 years from 1902, I noticed this as a significant and peculiar strand in the correspondence, the father writing to the son seeking praise and support for the work he was embarking on, the son magisterial and distant, at times haughty in his response, the father all filial in his tone.

"I am finishing a story and am longing to read it to you," he wrote in 1902, and soon again: "If I get my story finished I think you will be pleased." In 1908, already in New York, he sent his son two stories he had written. "I don't know what you will think about them," he wrote. A month later, when he had received no reply, he wrote again: "I fear your not writing means that you don't care for my stories (possibly condemned unread)." The offhand reply from his son came a year later: "I have found your two stories – they were among papers of Lady Gregory's. I must have lent them to her and asked her to read them. I send them to you. The one without a name is much the best, I think."

That year, the father began to write about a play which he was thinking of writing. Four years later, he had still not written it. In February 1913 he wrote: "And as you may remember, Synge paid me one of his few compliments. He said I could write dialogue." John Butler Yeats must have known, as he wrote this, that Synge did not believe that WB Yeats could write dialogue. Three years later, however, he had still not written the play: "You know I have a play in my head and mean some day to write it … And I bet if it is written it will be a success." His son, by this time, had had almost a dozen plays performed.

Soon, the father began to send his son poems he had written, but he got no response. When the play was finished, he had it typed. "I sometimes wish," he wrote, "that it had been possible for you to have consulted with me about your plays. I think I have a playwriting instinct, and that my play … proves it." In June 1918, he wrote: "Why don't you tell me about my play. You need not be afraid to praise [it] … I feel sure that someday it will be acted and be a success." He was almost 80 at this time. Four days later his son replied, having worked out a new and ingenious way of killing his father: "You choose a very difficult subject and the most difficult of all forms, and as was to be foreseen it is the least good of your writings. I have been reading plays for the Abbey Theatre for years now, and so know the matter practically … It takes a lifetime to master dramatic form."

That Naipaul and Borges and Yeats flourished in the shadow of a failed father are interesting examples, and there are others too. These include James Baldwin and Barack Obama, who both began their autobiographies with the moment their father had died. Baldwin's Notes of a Native Son begins: "On the 29th of July, in 1943, my father died." Obama's Dreams from My Father begins: "A few months after my twenty-first birthday, a stranger called to give me the news." Both men then set about establishing their distance from their fathers almost as a way of establishing their right to speak with full authority, to make clear that they had invented themselves and that the story they would tell would be one of pure personal autonomy.

But there are other writers who did not seem to feel this need. Among them is Samuel Beckett, whose relationship with his father seems to have been loving and easy. In April 1933 he wrote to a friend: "Lovely walk this morning with Father, who grows old with a very graceful philosophy … I'll never have anyone like him." And then, two months later, when his father died, he wrote: "He was in his sixty-first year, but how much younger he seemed and was. Joking and swearing at the doctors as long as he had breath … I can't write about him, I can only walk the fields and climb the ditches after him."

With Beckett, the mother was the problem. In 1937, when she had left him alone in the family house with a cook to make his meals, he wrote about how pleasant the house was in her absence: "And I could not wish her anything better than to feel the same when I am away. But I don't wish her anything at all, neither good nor ill. I am what her savage loving has made me, and it is good that one of us should accept that finally … I simply don't want to see her or write to her or hear from her." The following year, however, he wrote to his friend from Paris, suggesting that he could not escape her: "As you can imagine I am not anxious to go to Ireland, but as long as mother lives I shall go every year."

While it is easy to see old Ma Beckett in the work of her son, it is hard to imagine her actually reading his novels or going to his plays. The mother of John Millington Synge, another Dublin Protestant matriarch, did not go to the theatre at all. Not one member of Synge's family ever saw his work. At his funeral the theatre people and the family faced one another like two warring tribes.

Although they seemed to have little in common, Synge made sure that he returned from Paris every summer to have long holidays with his mother. In her diaries, she was worried about him, his delicate health, his lack of religion, but there is also immense affection for him and almost no anger against him. They played music together, and she followed his movements with interest, writing to another son in 1898: "I had a very interesting letter from Johnnie last week … He is now on Inishmaan Island – went there in a curragh and is much pleased with his new abode, a room in a cottage inside the kitchen of a house … and he lived on mackerel and eggs and learns Irish; how wonderfully he accommodates himself to his various surroundings."

Two years later, Mrs Synge invited a woman called Rosie Calthrop to join herself and her son on holiday. She grew jealous of the attention Synge paid to the younger woman. "It was rather aggravating to me," she wrote to another son, "he wanted to put me aside entirely." Thus in the demure triangle on holidays in Wicklow began the seeds of Synge's The Playboy of the Western World. He transformed his own quiet self into a young man who boasted that he had killed his father, as Synge had done indeed by becoming a writer. His wooing of Rosie became Christy's wooing of Pegeen Mike, while his mother, the Widow Synge, found herself transformed into the Widow Quinn. The idea that her life would be used in this way would, of course, have killed poor Mrs Synge. As he began to work on the play, her son must have found that he had invented a new and effective way to kill his mother.