It is probably the hardest question of all - the question that after war or conflict asks us and makes us look into the past. It is the unfinished business of this peace process - the next thing after all those other things - ceasefires, decommissioning, policing and that remarkable political arrangement that has given us the era of Paisley and McGuinness.
That has been the journey out of conflict - the road to this point.
Now, we live in a place of many questions that need answers.
The Healing Through Remembering Group - which takes in so much opinion from so many different sides - calls it making peace with the past.
Dr Brandon Hamber has just recently been appointed its new chairman.
"One has to understand that any debate about dealing with the past has the risk of being swayed politically in any context whether it's here or anywhere in the world," he says.
"You can hear the same debates about whose truth is going to be told, whose truth isn't going to be told and what issues are you going to look at."
Brandon Hamber hears it in Northern Ireland, and has heard it elsewhere.
He was born in South Africa, grew up there, is a clinical psychologist and describes political violence as his specialist area.
In Johannesburg he worked for a long time in the Centre for the Study of Violence and Reconciliation.
"The project that I specifically headed up was a project which focused on the Truth and Reconciliation Commission in South Africa, and part of my job was to work a lot with the victims who testified before the commission ¿ (to) set up support services and structures."
In that study centre they also started to do comparisons - to explore conflict situations elsewhere and what happened and didn't happen afterwards.
"So in a similar way in Northern Ireland, people now are looking at other contexts. We looked at contexts that had various processes, and contexts that didn't."
He brings all that international experience and learning to the debate and discussion here - brings an outside eye and voice to all of that.
"I think international lessons would tell us, on the whole, the past doesn't just go away, and that it stays there in some shape or form," he says.
"That doesn't mean that you can't engage in different levels of forgetting to deal with that, but my personal view would be one that you can't really escape the past. And, certainly, when you speak with a lot of victims, they remember the past every day."
Here, this question of the past raises all sorts of worries and fears - that this is the Provos trying to re-write the narrative, that it is war by other means on the security forces, that the whole collusion debate is a propaganda weapon to attack the police and Army, and that all this digging into the past could damage or destroy the politics of the present.
For some it is that scary - that frightening, something to be left alone.
But Brandon Hamber is right - you "can't really escape the past".
He has about 10 years experience of Northern Ireland now. He first came here in 1996 and has been living here for the past six years.
At the University of Ulster he is a senior lecturer and research co-ordinator of INCORE – a United Nations research centre for the study of conflict.
His role as chairman of Healing Through Remembering coincides with the appointment of the consultative group headed by Lord Eames and Denis Bradley and asking the question of how to address the violent legacy of the Troubles.
"It can't just be more of the same," he argues.
"There has been a Northern Ireland Affairs Committee that has done a report. Healing Through Remembering has done seven years of really hard work on this and brought to the table serious options that have been thought through in some cases for two or three years. So it can't simply just be a reflection back of that ¿ I think if it's to be worth anything it has to come with a direction. It has to basically be making some form of a recommendation that can be debated and perhaps rejected. But it just can't reflect that there is a complex debate out there."
I then asked did he think there was an appetite within government to begin to answer the questions of our past.
"I think in any society there is always a deeply ambivalent view about whether one should look at the past," is how he begins to respond.
"And on the whole, certainly when it comes to governments, and certainly when it comes to groups who have committed violence, they're generally fairly reluctant to go back and look at the past and account for their role either directly or indirectly in the past.
"So, I think that that's a fairly universal sense of reluctance about those things. That doesn't mean there aren't individuals, there aren't parts of those organisations ... or that it's not possible to get to that point. But I don't see at this moment in time a wholesale voice coming from the political parties, and from the governments really committing themselves to a deep engagement with how they are going to deal with the past."
The scattered approach that we have at present, of public inquiries, the Historical Enquiries Team and all of the other various bits of research including the work of Healing Through Remembering, is in Brandon Hamber's view how you normally build to something more structured.
"I think you always start from a fairly muddled place," he says.
"My personal view would be one that ultimately it probably is better to come up with a structured view¿and if not a structured view at least a way and a view that has been discussed and agreed and there is some sort of consensus."
That is the next piece of work - the making of a place and a process that allows the peace to ask its questions of the war.