It has been remarked that my choice of reading material for a holiday is not 'happy'. The American Civil War, a biography of Leonard Cohen, and now a book about the systematic extermination of Jews in Poland in 1941-2. OK, I see the point.

However, that is just for starters. And the reason I am sitting with my books and iPad in a cafe (with wifi) by a lake while my wife and friends do something else is because I have a seriously dodgy shoulder awaiting treatment when I get back to Bradford.

Right, that's the explanations and excuses dealt with.

Anyway, we had a conversation over breakfast this morning about how individuals, communities or entire nations manage to collude in inhuman behaviour while then proving totally incapable of coming to terms with that behaviour later. Austria has never seriously addressed its complicity with Nazism and the Final Solution; Switzerland's neutrality during the Second World War allowed it the freedom to cover both heroism and quiet cruelty; Rwanda sought to blame the Belgians and the French for sowing the seeds of genocide only twenty years ago.

We were discussing how the ground for dreadful collective behaviour and individual complicity in it is laid by years of cultural and linguistic corruption. Turn Jews and Bolsheviks into categories of 'enemies' and it becomes easier to justify getting rid of them. Spend years referring to 'the other tribe' as “cockroaches” and stamping them out becomes reasonable as well as achievable.

This reminded me of something I heard years ago at Greenbelt. I think it was the great and late-lamented Mike Yaconelli who claimed that the most common cause of death of cattle on the great plains of the American mid-west was “being hit by a train”. Trains and railway tracks were hard to find in the vast expanses of empty land. And the cows didn't set out to find them in order to get flattened by the iron horse. They simply put their head down, nibbled the nearest bit of grass… then moved on to the next piece of grass… and then the next bit… until they had moved a very long way and found themselves nibbling grass in front of tons of moving metal.

They nibbled their way to destruction.

People don't set out to collude in genocide. They just keep their head down and their eyes narrowly focused. They attend to the immediate business to hand and don't look up to see the bigger picture. But, one day they find themselves in front of a train.

Which is how and why Ordinary Men end up doing extraordinarily terrible things to other people.