In the West, we tend to assume that the greatest threats to democracy and liberty come from outside. We think of the totalitarian systems of the last century or fundamentalist terrorism today, but we fail to recognise the viral strain that has developed out of our own entertainment industries.

Over the past dozen or so years, television and movie-makers have managed to blur the border between fact and fiction to an unprecedented degree. They pretend increasingly that their film is based on a true story. Every device possible, from computer-generated imagery to place names and dates thrown onto the screen seek to suspend the disbelief of historically illiterate audiences. Alarmingly, the new technology has coincided with a dramatic growth in conspiracy theories.

The author Damian Thompson has labelled the phenomenon “counterknowledge”. This includes the propagation of totally false legends. They may well stem from a completely unbalanced person who genuinely believes in a conspiracy — usually a government one — and who, through the internet, makes it sound plausible to tens of thousands, even to millions of others who also have grievances and are eager to believe the worst. This is done by seizing upon one or two minor discrepancies in a government report, then joining up all the wrong dots to create a monstrous fable that runs completely counter to the facts.

Examples of counterknowledge include the notion that Aids was created in a CIA laboratory, that Princess Diana was murdered by the Secret Intelligence Service, and that the 9/11 attack on New York was orchestrated by the Bush administration. The dramatic decline of traditional moderate forms of religion has resulted in a spiritual void and thus a desperate need to believe intensely in something. This has accompanied the “Wikipedia age”. A populist notion has developed that any individual has the right to correct or change the truth according to their own beliefs. It is, of course, the democratic ideal taken to its most grotesque extreme. But in reality it is the opposite of democratic. It is the easiest way for the demagogue to exploit gullibility and ignorance.

The home-produced movie Loose Change takes the ultimate conspiracy-theory approach to 9/11. It is now said to have been seen by more than 100m people on the internet. A few weeks ago, a leading Russian TV channel broadcast Loose Change to mark the anniversary of 9/11. The film was accepted as completely true by the presenters and the studio audience, who debated it in a three-hour prime-time programme.

Studies of internet sites reveal an unholy alliance between left-wing 9/11 conspiracy theorists, right-wing Holocaust deniers and Islamic fundamentalists. Many Muslims throughout the world now believe that no Arabs were involved in 9/11. Significantly, Islamic websites have also been learning from American creationists and have eagerly embraced their theory of intelligent design, which attributes the origin of life to a higher power and opposes theories of natural selection.

In a post-literate society where the image is king, the scope for mischief is almost without limit. I suspect that it will not be long before we see a Holocaust-denial movie. It could take the form of a Da Vinci Code-style thriller, and be packaged as straightforward entertainment.

The commercial potential for such a project is huge, above all in the Middle and Far East. If it were banned under Holocaust-denial legislation in some European countries, this would only convince conspiracy theorists that the Holocaust is a Zionist exaggeration or even invention. Already in British schools, many teachers have stopped mentioning the Holocaust to avoid offending Muslim students. This is because, according to one survey, only 29% of Muslims in Britain accept that the Holocaust took place as western history books describe it.

Political correctness is so easy to exploit. Universities in the United States, supposedly the guardians of intellectual rigour and scientific proof, have been cowed into accepting courses that clearly reject normal standards of evidence. This is perhaps the logical extreme of the anti-hierarchical revolution begun in the 1960s and now taken to a ridiculous and dangerous degree.

It may sound alarmist when one talks of these attempts to fragment proven reality. Yet the effects of counterknowledge and pseudo-history might develop a bigger threat to liberal democracy than the authoritarian onslaughts of Stalin and Hitler. This new insidious power to produce intellectual and scientific chaos is easy to underestimate.

It should be the duty of not just every scientist and historian, but also of every writer, publisher, movie-maker, TV producer and ordinary citizen to fight all attempts to exploit the ignorance and gullibility of audiences. Today’s silly conspiracy theory in the West can easily become tomorrow’s article of faith in the world at large. Quite simply, we play with facts at our peril. From selling fiction as truth in movies to peddling the big lies of counter-knowledge is not such a very big step after all.

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