I'm troubled by what the jailing of David Irving has revealed. There are many comments here by young people (younger than me anyway) who all broadly agree that free speech is absolute and Irving is a victim. More worrying is the supporting statements being made. Some are just absurd and ignorant - like claiming he has been jailed for thought crime; no. he said it - but others clearly believe that there is doubt about the Nazi Holocaust. This doubt is precisely the aim of the Holocaust denyers. Presumably these views are more widespread than the few I've seen.

David Irving has spent his career employing a technique known to academics as reductio ad absurdium. It is a legitimate tool. its used in physics proofs for instance. It has no place in the study of history however. It means that we should not believe in the big picture until every last dot and comma of the constituent details have been proved. In Irving's case it means asserting that we cannot be sure about the approximate number of murders committed by the Nazis because we cannot prove cause of death for every victim. That we cannot believe that victims were gassed at Ausschwitz because we cannot excavate any remains of the chambers. That we cannot hold Hitler responsible because we cannot find a single execution order with his signature on.

Following this model we would not accept that during the eighteenth century the urban population of England rose from 20% to 60% because we cannot identify the old and new addresses of every individual involved. We would not accept that slaves were transported from Africa to America because we could not trace each and every African American's family tree back to Africa. We would not accept that Louis the sixteenth was executed by revolutionaries in 1790 because we cannot find any trace of the guillotine with which they accomplished their task.

This isn't history.

There are serious historians working on the Nazi period who are revising commonly perceived truths. They aren't insulting people by quibbling about the figures they are trying to answer the real question, how did the Holocaust happen ? Many people like to blame it on the madness of Hitler, its simple and neat and avoids any difficult questions. The truth is more complex but well worth investigation because the more we can understand how it happened the more chance we have of preventing it happening again. For instance, the first large scale transportation of Jewish people from Germany was at the local initiative of the Nazi in charge of Hamburg. It wasn't part of some great planned genocide, it just occurred to him at the time. Not popular with some to say so but this is the truth and it is part of the legitimate historical process to reveal it. I actually find it heartening; it means that as late as 1941 the Holocaust could have been prevented if enough people had done the right thing.

I suspect this willingness to treat Irving's views as being as legitimate as anyone else's stems partly from a blanket scepticism; part of the disengagement with political parties that is prevalent among younger British people. Of course, like the stopped clock, if you are sceptical about everything you will agree with everyone on something. You make no net political contribution; its just another form of liberalism. But that doesn't make it OK. People who are so atomised that they can entertain the idea of absolute freedoms with no concern for the affect on society are more vulnerable to Irving's poison.

Doubt is a powerful weapon. The Nazis began with doubt. They encouraged non-Jewish Germans to doubt that Jews had fought in the Great War for Germany. They encouraged them to doubt that Jews felt themselves to be German. They encouraged them to doubt that Jews were honest. David Irving has never applied his method to the Agrarian Revolution or the Gunpowder Plot. He's not interested. His aim has been to instil doubt about the Holocaust so that Fascist organisations like the National Front and the BNP would face less opposition. I stood three feet from a couple of Nazis in suits in Lewisham police station in 1993. They are frightening people. They are every bit as dangerous as the thugs who daub Synagogues with swastikas, poor petrol through the letter boxes of asians and murder black students. Stop them, as Malcolm X advised "By any means necessary".