I have just spent the weekend in the company of three men from Northern Ireland. Or are they Irishmen? Are they, in fact, from the United Kingdom? Could they even be all three?
For an Englishman from Manchester, the nomenclature, and what it means in terms of identity, is all rather confusing. This topic has been in the news recently with Rory McIlroy, the world's number one golfer and a man born in the Northern Irish town of Hollywood, being asked whether he would represent Ireland or Team GB in the 2016 Olympics when golf becomes part of the Games. The subject is germane because McIlroy, pictured, who represented Ireland many times as a junior, told a journalist that he has always thought himself more British than Irish.
"Maybe it was the way I was brought up," he said, "but I have always felt more of a connection with the UK than Ireland."
The whole question, of course, is bound up with religion: McIlroy is a Catholic and, although he was brought up in an affluent, mainly Protestant area, it is extremely unusual for a Northern Irish Catholic to feel a primary affinity towards Britain.
International sportsmen exist in a world where politics rarely intrudes, but McIlroy has no such excuse: before he was born, his great-uncle was shot dead by loyalist paramilitaries, and although as a 23-year-old he'd be more familiar with a Northern Ireland at peace than war, all around him will have been the iconography and human cost of the Troubles.
Does it really matter who McIlroy may or may not choose to represent in four years' time? Well, yes, actually.
As a new Northern Ireland emerges from the decades of separatism, the question of national identity is still extremely relevant in a way it just isn't for most of us. It may have been unwise for McIlroy even to contribute to such a highly charged debate: he could easily have offered the sportsman's traditional response that such matters are for other people, and that he was primarily concerned with his putting rather than politics.
But the fact that McIlroy felt able to discuss in a such an honest fashion a subject that is capable of opening historic wounds and exposing age-old prejudices reflects well on him, and on a new settlement in the province. I asked my friends who they would choose to represent in the extremely unlikely event of their achieving sporting pre-eminence.
They are all Protestants, and two picked United Kingdom while the other said he would opt for Ireland. It provoked a rather lively debate, which suggested to me that the issue of national identity is very much a live one in Northern Ireland, and one from which interlopers like me should steer clear.
"I'm Northern Irish. I hold a British passport," said Rory McIlroy. "So there you go." I suspect it's not quite as simple as that, and I'm sure Rory knows that, too.