As I tried to explain, when Archduke Ferdinand was shot in Bosnia, I doubt anybody sat back and said, ‘wow, I bet that leads to 17m people dying in a huge world war.’ Equally, when Marx and Engel sat down for a beer and decided to knock out some essays, the waiter bringing them their drinks didn’t pause to worry that these guys might come up with an ideology that would lead to the death of tens of millions of people. This hadn’t happened before, so nobody was looking out for it. These things happen because we can’t see them coming. This century should benefit from the lessons of the 20th Century, yet at the moment it seems we are collectively blind to all of that.