CULTURE SHOCK: DAVID HARE is the master of so-called verbatim theatre in England, using the public record to create dramatic re-enactments of significant events. In his recent Royal Society of Literature lecture (reprinted in the Guardian), he answered the question that always hangs over such dramatisations of real events: "Aren't you telling us what we already know?", writes FINTAN O'TOOLE

In fact, Hare gave two good answers. “We think we know, but we don’t” – knowledge, even of widely publicised events, is usually vague. And in any case, knowledge itself is never enough: “it’s one thing to know, and another to experience.”

Hare's defence usefully encapsulates what is happening in the Abbey Theatre's documentary theatre piece on the Ryan report into abuse of children in industrial schools, No Escape. For anyone who has read the Ryan report, or even extensive summaries, the piece, compiled and edited by Mary Raftery, may seem to be an exercise in "telling us what we already know".

With the tiny exception of a list of towns in which there were industrial schools, every syllable of the text is taken directly from the report itself or from transcripts of evidence by religious order representatives at the commission's public hearings. In order to justify itself as a project for the National Theatre, rather than, say, Prime Time, the piece has to show that theatre adds something to that existing public record.

It does so in two important ways. Firstly, it implicitly confronts the idea of “knowledge” itself. The problem with the industrial schools was never that they were unknown. They were a huge physical and psychic presence in every corner of the country for most of the history of the State. The State itself did not, as Bertie Ahern put it in his formal apology to the survivors, “fail to detect” the existence of institutionalised violence against defenceless children. What happened rather was that at all levels – government, communities, the religious orders themselves – there was a mechanism of both knowing and unknowing at the same time.

One of the key things Raftery does in boiling down the thousands of pages of transcripts and conclusions is to include this system of denial in the narrative. By inter-cutting the reality as experienced by the children with the evasions of that reality by the Department of Education and the religious orders right up to 2005, she makes the slipperiness of “knowledge” central to the persistence of organised sadism.

And, of course, that evasion is continuing. How many people have actually read the Ryan report? How much has it been taken to heart? Have we, as a society, absorbed into our self-definition words such as "slavery" and "torture", both of which were practiced on a massive scale by church and State? At the most basic and urgent level, No Escapefunctions as a concentrated lesson in an Irish reality we would prefer not to know fully.

But this function could, arguably, be fulfilled just as well by a TV documentary, which is why it’s the second part of Hare’s answer – “it’s one thing to know, and another to experience” – that ultimately makes the case for theatre’s capacity to add something to what has already been done.

Theatre is an experience in the way that a piece of television is not. Its essence is public presence – both of other members of the audience and of the actors. By playing out before us the testimony of survivors and perpetrators – even in the cool, unemotional, carefully controlled manner of Róisín McBrinn's finely judged production – No Escapeforces us to accept their reality as our own. In the darkened theatre, confronting this devastating story that we cannot turn off with the flick of a switch, we experience our own tiny sense of inescapable confinement.

What theatre does to experience is, quite simply, to embody it. And this is what needs to be done with the abstract words of the report. Embodiment is entirely germane to the subject matter, for it is on bodies – young bodies starved, savaged, soiled and violated – that all of this was inflicted.

There is also the sound of the public voice, a sound that is not the same as the one we hear in our own heads when we read these horrors in the report. In performance, the cold, brilliantly brutal lists in the report – of the various implements with which children were tortured, or the numerous ways in which in which they were sexually violated, or the variety of places in which abuses occurred – become dark echoes of the litanies of the rosary.

To say all of this is not to say that No Escapematters primarily as a piece of theatre or a work of art. There is artistic merit in the skill with which it is compiled, edited and performed, but the piece works precisely because those skills are always at the service of something else: the communication of a necessary truth. And the very effectiveness of the piece raises another question that is not essentially artistic: what to do with it? No Escapefinishes its short run at the Peacock tonight, and from the point of view of the scheduling of a theatre, that is entirely logical. But really this piece belongs to something much bigger than the theatre. It belongs to the survivors and, beyond them, to the national memory. It is part of the long, difficult and utterly crucial task of finally absorbing this great crime into our collective reality.

Abbey director Fiach Mac Conghail has already indicated a desire to take No Escapeto England, where so many survivors of the industrial schools took refuge. That is undoubtedly right. But it is no less important that it be seen in every town in Ireland that had an industrial school. It belongs to each of them, as part of their own community and history.

There is still a huge task for Irish culture to take collective ownership of this terrible story. Seeing this piece is one small but meaningful way to begin that process.