In the course of an hour-long interview, Pat Sheehan uses words like "antediluvian" and speaks of neo-Aristotleism and of Sisyphus – the figure in Greek mythology who was condemned to toil forever pushing a rock up a hill.
He has met Mandela. He has a first-class honours degree in politics and philosophy. He skis. He is an avid cricket fan. Although all of the above might suggest the man is perhaps a senior British diplomat, the fact is that Sheehan had a reputation as one of the IRA's most committed activists. He twice served lengthy sentences for IRA attacks, and went on a hunger strike that took him to the point of death.
He is clearly not your average ex-IRA bomber.
The IRA has disbanded, but Sheehan has remained highly active in the republican undergrowth. Now he is being propelled into the public spotlight by taking Gerry Adams' place in the Belfast Assembly.
The Sinn Fein president is moving south across the border to stand for the Dublin parliament, handing over his seat in Belfast to Sheehan, who is adamant that he will never be a conventional career politician.
Did he ever expect, while locked up in the Maze prison at Long Kesh, that 30 years on he would become a Sinn Fein representative?
"Absolutely not," he replied. "In fact, I didn't believe I would survive my imprisonment, I thought I would end up dead – that's how bleak the situation was back then."
In 1981, 10 republican prisoners starved themselves to death, led by Bobby Sands – revered ever since as one of the IRA's greatest icons. Sheehan was on the same hunger strike, and was due to be the next to die. Sands died after 66 days refusing food. Sheehan starved himself for 55, surviving only because the IRA called off the entire project.
"I was the longest on the hunger strike at the time it finished," he recalled. "If it had continued I have no doubt that I would have died. I was absolutely prepared to die.
"Several days earlier I was examined by a consultant who told me my liver was beginning to shut down, and that even if I ended it there and then he couldn't guarantee I would survive." That was when he was 23 years old: would he do the same today, at the age of 52? After a pause he replied: "The only thing that's really different on a purely personal level with me now is that I'm a parent.
"It puts into perspective for me the massive sacrifice that Bobby Sands made, because his son was eight years old on the day of his funeral," he said. "I don't know if I could possibly make that sacrifice, now that I am a parent, to leave my son to grow up without a father."
Sheehan's late wife, Siobhan O'Hanlon, was also a republican of note. She too was jailed for IRA activities, though she denied media allegations of involvement in the 1988 IRA mission to Gibraltar when three of its members were shot dead by the SAS. She went on to become a close aide to Gerry Adams, acting as a conduit between him and Tony Blair and attending many key meetings, including the first Adams-Blair encounter in Downing Street.
Sheehan met O'Hanlon in 1987, after serving a 15-year prison sentence; she too had been in jail.
But two years later he was back inside for a 21-year stretch, for leaving a bomb at a security checkpoint. O'Hanlon visited him in prison and their relationship, he explained, "eventually developed into something else. When I got out of prison in 1998 we got together, and our son was born nine months, exactly to the day, after my release." She died of cancer in 2006.
Sheehan's first jail term featured his hunger strike, while during the second he took his degree. Did studying philosophy cause him to reconsider the violence of the IRA?
"I think when you're in a war situation, I'm not saying ethics are put on hold, but I think you have a different template. Irish republicans can justify, and I can certainly justify within my own mind, the use of armed struggle here in the Seventies, Eighties and Nineties," he argued.
"But I don't try to justify it now. I think strategically, politically, morally it's wrong. We're in a different situation. In war it's easy to go out and kill people because you believe that's the right thing to do.
"I'm not saying it's right in every circumstances to kill, that everyone who was killed in the war ought to have been killed, or that it was right or justifiable to kill them. There are many circumstances in which the IRA was unjustified in killing people here."
Then he came up with an unusual description of the Irish conflict: it was, he remarked, "probably quite civilised, if that's a proper description to use". Civilised? Was the IRA civilised, was it a civilised conflict?
"If you look at it in the round," he contended, "the type of mass killings and genocide in other conflicts didn't happen here. The IRA, for example, if it had wanted to kill Protestants, could have left a 1,000lb car bomb on the Shankill.
"Here there was never that sort of blood-letting. It probably doesn't feel like that for victims, and when we were in the midst of it all it certainly didn't feel like that, but it was certainly less intense than a lot of conflicts.
"People will talk about the Shankill bomb, or the Poppy Day killings in Enniskillen. I would in no way try to justify those IRA operations, but what I would say is that in most of those situations I don't believe the IRA went out to kill civilians."
Sheehan's first brush with death came as a teenager, when loyalist gunmen came to his door in west Belfast and, finding he was not home, fired shots at his father.
The family was at that point living in a mainly loyalist area, but until then there had been few problems: "All my friends from round there were Protestants, we used to follow the Orange bands around," he remembered.
Then there were brushes with the army. "It was a frightening experience for a 14-year-old to be arrested and taken away and treated and questioned aggressively," he said.
At 15 he joined the IRA's youth wing; at 17 he was a fully-fledged member involved in bombings; at the age of 19 he was sentenced to 15 years in prison; four years later he was on hunger strike.
One of his recent republican roles has been as a "legacy coordinator", engaging in discussions on how to deal with the past, exploring truth-recovery processes. It is a role that has brought him into close contact with loyalists as well as with former soldiers and police.
According to Sheehan: "It's a big, big issue. Sometimes I think it can't be done; other times I think people are willing to try. If there's any way we can resolve the issue through dialogue, then let's try and do it." But a drawback, noted by Sheehan and others, is the fact that Protestant paramilitants are effectively disowned by the political parties within their own community: "They just don't have any real leadership there," he said.
"Former republican prisoners, when they're released, by and large are held in fairly high esteem within their community. On the loyalist side it's the complete opposite – they're marginalised."
Sheehan is unusual among republicans in following cricket. His family is strongly associated with Gaelic games but, he says, "I'm definitely a cricket fan, I think it's a great game."
His interest began during his long spells in jail. "It's probably the only place you get to watch a full test match," he explained. "It's a game where you can sit back and relax." And who does he support? He laughed: "Anybody who's playing England."
When he visited South Africa, together with his wife and Gerry Adams, they were shown around the former Robben Island prison by two government ministers who, with Mandela, had been held there.
"Gerry was driven round by police drivers, in a convoy of two or three cars," Sheehan related. "Sirens blazing, traffic moving out of the road." When the ministers spoke about their experiences they discussed hunger strikes. Sheehan marvelled: "When they spoke about a hunger strike they called it a 'Bobby Sands' – they said they had thought of doing a 'Bobby Sands'.
"At the time of our protests we were pretty isolated from the outside world. It felt like the loneliest place in the world, sitting in a cell in a prison hospital basically waiting on your own death. At the time we weren't aware of the massive impact of it, but it showed republicans that electoral politics could be another side of struggle."
So back in 1981, as he sat in prison readying himself for his death, did he assume that a united Ireland would have arrived by now?
He replied: "Well, I've never had a date in my head for Irish unity. When you become involved in struggle it's a sort of lifelong vocation. That's the way struggle is – there's no end to it, it doesn't stop, unfortunately. It's like Sisyphus pushing the stone up the mountain."
A life in brief
* Patrick Sheehan was born in 1959. His father was a builder, his mother a housewife.
* After joining the IRA as a teenager, was subsequently twice imprisoned. Took part in two prison hunger strikes.
* Since leaving prison has worked with former IRA prisoners; is involved with Sinn Fein's international contacts, including the Middle East and South Africa; coordinating coming anniversaries of hunger strikes.
* He is a widower with one son. His late wife, Siobhan O'Hanlon, worked closely with Gerry Adams.