After every atrocity, the screens and airwaves fill with terrorism experts trying to fill the void in rational language opened up by the latest unspeakable act. But in Ireland most of us are terrorism experts.

It is not an accomplishment we like to boast of or even acknowledge. Yet pretty much anyone who lived an adult life through the Troubles – which is to say any native of the island over 40 – knows an awful lot more about terrorism than most academic experts. And it might be time that we both owned up about this knowledge and tried to do something positive with it.

There are three big and valuable things we know about terrorism in Ireland.

The first is that people who commit and support monstrous acts are not necessarily monsters. Which of us does not know someone who was active in a terrorist organisation or who was a member of a party linked to a such an organisation or who gave money to “the cause” knowing that it would almost certainly be used in some way to aid the commission of terrorist acts or who, at the lowest level of involvement, excused a horrific atrocity, usually with a diatribe beginning with those two great weasel words “what about . . . ?”

From this personal acquaintance, we also understand a deeply disconcerting truth: that these people are in general normal, well-adjusted and in other respects perfectly decent human beings. This is not to say that terrorist organisations do not attract the psychopaths and the sadists – it is very obvious, and in a grotesque way rather comforting, that they do. It is much easier when the people who think it’s justifiable, for example, to put a bomb in a packed pub, are clearly different from the rest of us. But in Ireland we live with the truth that most of those who think like this are neighbours and friends, workmates and classmates, brothers and sisters, fathers and mothers.

Unsettling

In Ireland, we know that the line between Them and Us, the civilised and the barbarians, is not nearly so clear-cut as we would like it to be when we see the carnage on the Promenade des Anglais. And this knowledge, however queasy, is valuable to the world at large.

It tells us that the words that come to our lips when the innocent are slaughtered – mindless, evil, monstrous – are emotional distress signals, not useful descriptors. Terrorism is not mindless – it has a serious purpose: to foment an apocalyptic civil war or global conflict. Revulsion is therefore not enough. To respond to terrorists we have to understand what their purposes are and how we can thwart them – which is not by constantly echoing their cry of “war”.

The second valuable thing we know in Ireland is that terrorism is not a virus that takes hold only among people outside the white European and American mainstream. In particular we know that the current effort to frame terrorism as inherent to Islam is nonsense. We Irish know a hell of a lot about terrorism that draws on biblical Protestant rhetoric and identity. And most of us know even more about terrorism that draws on Catholic rhetoric and identity. In particular, we “get” the cult of martyrdom – if you’ve forgotten this, go and see Brendan Byrne’s riveting new documentary about Bobby Sands and the 1981 hunger strike, 66 Days.

Why is this experience useful to the world? It shows the stupidity of anathemising a religion because some who claim to identify with it are terrorists. Donald Trump and Newt Gingrich, for example, could benefit from a crash course in the Troubles to remind them that Isis no more equals Islam that the UDA equals Protestantism or the IRA Catholicism.

Suspicion

Third, we Irish understand the folly of creating a suspect community. Few white, western Europeans know as we do what it’s like to be an object of suspicion simply for who you or, for example, for the way you talk. We know that this is very unpleasant but much more importantly that it is utterly counterproductive. We know how it makes people on the receiving end feel.

People who in fact have no truck with terrorists begin to feel that since they are being treated as in some way responsible for what those terrorists do, they are being forced on to the wrong side of a dividing line between them and the state. They resent this and in their resentment they don’t trust the authorities to deal fairly and justly with any information they might give them – the small incidents that a community witnesses from the inside and that add up to crucial intelligence.

If we really feel solidarity with the victims of the current terror campaigns in Europe, we need to start talking collectively about these things we know. We have worthwhile things to say to our friends and we can say them with the particular authority of having generated from within our own communities and cultures some of the world’s most resilient and effective terrorist organisations. But of course in order to do that we’d have to do something many of us are still very uncomfortable with – acknowledge our own recent history.