Hinterland, the seventh play in Sebastian Barry's series on the family, concerns the father figure. Declan Kiberd traces the family's cultural role in the creation of the State.

A happy family, like a contented nation, is unlikely to have hair-raising adventures. The great works of literature tend to begin with a frustrated character who feels impelled to break out of a social structure. In that sense, many of our cultural narratives focus on some sort of dysfunctional family.

Perhaps that is what Tolstoy meant when he wrote at the start of Anna Karenina that all happy families are alike, but that each unhappy family is unhappy in its own way. His implication was clear: good books deal with the latter.

"Wherever there is Ireland there is the family," remarked G.K. Chesterton with something like envy, "and it counts for a great deal." He made the comment after a visit to the artistic family of John Butler Yeats, in London. The portrait-painter and his poet son had so often raised their voices during conversation that their neighbours on Blenheim Road concluded the two were coming close to blows. Then one of the Yeats girls patiently explained that this was simply "the Irish way", at home and overseas.

Why was family life so greatly intensified in Ireland during the past century and a half? One answer might be that it was intensified everywhere. Unhappy with an industrialised society, artists identified themselves with the child's problem of adjusting to an adult world. With smaller families and a reduced level of infant mortality, the depth of feeling between parent and child became ever more charged with symbolic meaning. What Freud would call the family romance had begun.

In Ireland, however, particular conditions gave that romance added complexity. Because the country in the 19th century was a colony, the family was often the largest social unit with which the common people could identify. The law, the army, the civil service, even the institutional churches seemed to belong to the ruling elite, but the family offered a private space in which the writ of official power could not run.

This is one reason why it became, in the eyes of republican insurgents, a unit fit for organised resistance to overweening power. Because the men in such families lived in constant fear of being imprisoned, the women had to learn the art of supporting their families on their own, and many came to assume equality with men as of right. Such families became, in the words of Carol Coulter in her pamphlet The Hidden Tradition, "alternative models of human organisation". It was in these conditions that the idea of a republican polity was passed on to children.

In every family a moment will come when children challenge parents about the ways in which business is done. In a free and functioning society, that revolt has meaning, for the older generation is generally glad to face the possibility of renewal. So it accedes on many points to the young and, as both parents and, in due course, children have their hands on the levers of power, the result is social progress.

This does not happen in an oppressed community, however. As neither parents nor children exercise power, the revolt is meaningless in social terms and lapses back into the intensified squabbles of family life.

The family in occupied Ireland was no haven in a heartless world but a zone reflecting the disorder of the world outside. Its compromised father could seldom offer an image of convincing authority. As Albert Aemmi wrote in a similar situation: "It is the impossibility of enjoying a complete social life which maintains vigour in the family and pulls the individual back to that more restricted cell which saves and smothers him."

The classic texts of the Irish Revival often seem to be explorations of that theme. The over-intense, clutching relations between mother and son in them often arise from the fact that many women were seeking from sons an emotional fulfilment denied by their partners. But the women couldn't have achieved such dominance if the men had not abdicated very often from the role of father as well. Many gifted authors - James Joyce, J.M. Synge and Sean O'Casey - therefore sidestepped the obvious mother cliché, opting instead to investigate the deeper problem of the inadequacies of the Irish male.

Whatever the underlying situation, the clash between father and son in Irish writing seems to indicate a society unsure of its direction. And under conditions of colonial occupation, the only way to give meaning to the revolt of the young against parents was for both parties to seek revolution and gain access to the levers of power.

The tremendous contribution to the war of independence by many republican families helps to explain why the rebels, when they took power after 1921, went to such lengths to secure the practical and symbolic importance of family life. This became especially true of the Constitution of 1937, which treated the family as the bedrock of Irish society.

Its author, Eamon de Valera, had a strong personal investment in the image of the family as a cure-all. His own childhood had been greatly disrupted and so, in his later years, he came to yearn for the sort of family intimacy that had not been fully possible. He wrote that yearning into his most famous document.

The Constitution of 1937 signalled a significant change in the cultural meaning of the Irish family. From once being a zone of resistance, it was turned into one of State control, and from being a site of struggle it was turned into a means of counter- revolution.

The theory underlying the Constitution - and underlying so many Irish novels and plays - was that the family was in some sense a metaphor for the State. But the family was, increasingly, a fetish sponsored by leaders who despaired of ever building a true society. It became for some an alternative to the idea of the social. Egoisme à deux replaced the search for community, and in time some of the State's foremost scoundrels would defend acts of financial chicanery with the claim that "I did it for my family".

John McGahern's great novel Amongst Women has much to say on the theme. The old IRA man Moran quarrels with his one remaining comrade from the flying-column days and turns instead to the family structure for a compensating image of himself. "In a way, he had always despised friendship; families were what mattered, more particularly that larger version of himself - his family." Moran would use that structure as a screen for his weaknesses.

Many of the keynote novels of 20th-century Ireland, from Edna O'Brien's The Country Girls to McGahern's The Barracks, use the family as a unit by which to establish not so much the health of a society as the impossibility of a fully socialised people.

The bitter old joke that asks how you can write a novel of manners about a society that has none was often recycled. This critique is now the subject of a dissertation being completed by Giulia Lorenzoni, a young Italian scholar at University College Dublin.

What should have happened under the conditions of independence was obvious enough. Each family might have been expected to break into its constituent parts, even as the victorious national movement broke into its different social forces. Each person would have gained in individuality, with children further asserting their independence of parents and many parents taking a secret pride in being so comprehensively usurped. The free person should have been born as the creator of his or her own values.

That didn't often happen. The strong family is an institution that threatens all wider versions of human organisation, a fact well attested by the title of Ferdinand Mount's interesting book The Subversive Family. The family can indeed subvert bad regimes, but it can subvert the hope of good ones, too.

At its best, in an empowered and happy community, it can be the place where one learns to love, as a rehearsal for those acts of interdependence that are the mark of a civilised society. Butin a world whose systems don't work well, it can become a refuge for the sort of monsters and weaklings who never really believed there was such a thing as society anyway.

Declan Kiberd is head of the combined department of English at University College Dublin. His most recent book is Irish Classics (Granta)

Hinterland opens at the Abbey Theatre, Dublin, on Friday