Six years ago I was in a bar in Brussels when a young man came in and announced to the world in general that some idiots had flown hijacked planes into the World Trade Center in New York. He said "Bush is going to go fucking crazy, it's going to be World War fucking Three." I knew Bush was an idiot, but also knew he was remote-controlled by others, and therefore assumed this prediction was wrong.

Nonetheless, I wanted to know what he was talking about, so I rang up my wife, who had a television in her workplace permanently tuned to a news channel, and asked her what was going on. She told me that the World Trade Center was on fire, that 50,000 people worked there, and that she was feeling sick.

So I went into the European Parliament building next door and asked where there was a television I could watch. This wasn't as simple a question as I thought, but I ended up in the press centre watching CNN pictures of burning skyscrapers on a Spanish news channel. They didn't have CNN, which I thought strange. There were some pictures of celebrating Palestinians which later turned out to be archive footage unrelated to the events.

A plane was flown into the Pentagon; another crashed in a field, but there were few pictures of the one and none of the other. Unconfirmed reports of further hijackings arrived at irregular intervals and evaporated. After a while the skyscrapers collapsed. There was nothing more to see, no-one knew anything, so after some hours I went back to my hotel.

Many people made comments and predictions in the next few hours and days. Some said that things could never be the same again. Cynically and arrogantly I thought they were wrong, since nothing had changed: we had already known that there were idiots around who would like to do such things. I was wrong: when enough people think there has been a change, that in itself causes the change.

President Bush read a speech promising to hunt down those responsible. Nobody knew who that was. No-one claimed responsibility. Some said that Osama Bin Laden and Al Qaeda were behind the attacks. Osama Bin Laden said he was not. Since he is a murderous idiot of a particular kind of honour, I presumed this was the truth. And why should he lie about what in his eyes would be such a glorious achievement?

Articles in the press in the next few days and weeks addressed the new kind of terrorism we were faced with. 'Today's terrorists' were held to be different from those of the past. To address the new terror some very old means were used. As a result it is now no longer possible in much of the world to speak of 'freedom' because it has become a synonym for wars of aggression, the bombing of civilians, chaos, kidnapping, and torture.

Over the past six years it has become clear that the world was damaged that day when so many said how everything had changed. But what caused the damage was not the destruction nor the too many deaths. It was that belief that the world had changed, and the belief that we must change to match it.