Anyone who has had a passing acquaintance with physics has heard of Schrödinger’s Cat. Indeed, those of us who watched The Big Bang Theory TV programme can probably have a go at explaining it. So, here goes… it was a thought experiment designed by Schrödinger to illustrate the bizarre and mysterious behaviour of sub-atomic particles as described by quantum mechanics. They exist in a statistical ambivalence known as a super position, in which they are simultaneously in two or more states until they are observed, when they then collapse into a particular and, until recently, unpredictable state. In the hypothetical experiment, into the box with the cat, is placed a small amount of a radioactive substance which has a 50-50 chance of decaying and releasing a particle which will trigger the release of cyanide and kill the cat. So like the quantum particles, until the box is opened, and the cat observed, it exists simultaneously in two different states, namely ‘dead’ and ‘not dead’.

Yes, I do not understand it either but it does remind me of the position of the Irish/Northern Irish border. Since the Belfast/Good Friday Agreement we have had a ‘quantum’ border which has been allowed to exist and not exist at the same time. It is a border, yes, and can be seen as a wiggly line on the map with the Republic of Ireland on one side and the United Kingdom on the other. However, for those of us who cross it regularly, it effectively ceases to exist. Apart from working out how many kilometres an hour is 70 mph or how many miles an hour is 120 kph we drive through unimpeded. As both sides, Irish/Northern Irish or six counties v twenty-six, are in the European Union and customs posts, soldiers and watch towers have disappeared, effectively the border is also simultaneously not a border.

That is, until you look at it. Until you talk Brexit and the border/non-border becomes a major issue. Until it is observed and we are forced to make up our minds about it. Then it will collapse into a single state which is either a real, hard border or a virtual, backstop border or something else and at that point people are forced to take sides again. Up to this point a delicious but vulnerable ambiguity has allowed Irish nationalists to see no border and British unionists to see a border even though they are both looking at the same thing. Crucially, both can be seen to be content with the status quo at one and the same time. Once we are forced to make up our minds about it the two traditions will see it differently and there will be winners and losers as the relatively peaceful super position evaporates. The ambivalent state has provided a sort of stability but a real border or a genuinely absent one forces us to take sides again.

Politicians often use the phrase ‘let me be absolutely clear about this’ when they want to convince us about something. However, sometimes clarity can be dangerous. The ambiguous nature of the border since 1998 has been a major strength and a vital part of the tentative and complex political and social jig-saw puzzle that has delivered a relatively peaceful normality for us all since then. Whatever the outcome of the Brexit negotiations it seems that we are in danger of losing our Schrödinger border and having something else in its place.

The real worry then is we may well have killed the cat.