2008 : WHAT HAVE YOU CHANGED YOUR MIND ABOUT? WHY?

I am a heretic. I have come to question the key assumption behind this survey: "When facts change your mind, that's science." This idea that science is an objective fact-driven pursuit is laudable, seductive and - alas - a mirage.

Science is a never-ending dialogue between theorists and experimenters. But people are central to that dialogue. And people ignore facts. They distort them or select the ones that suit their cause, depending on how they interpret their meaning. Or they don't ask the right questions to obtain the relevant facts.

Contrary to the myth of the ugly fact that can topple a beautiful theory - and against the grain of our lofty expectations - scientists sometimes play fast and loose with data, highlighting what that suits them and ignoring stuff that doesn't.

The harsh spotlight of the media often encourages them to strike a confident pose even if the facts don't. I am often struck by how facts are ignored, insufficient or even abused. I back well-designed animal research but am puzzled by how scientists chose to ignore the basic fact that vivisection is so inefficient at generating cures for human disease. Intelligent design is for cretins but, despite the endless proselytizing about the success of Darwin - assuming that evolution is a fact - I could still see it being superseded, rather as Einstein's ideas replaced Newton's law of gravity. I believe in man-made global warming but computer-projected facts that purportedly say what is in store for the Earth in the next century leave me cold.

I support embryo research but was irritated by one oft-cited fact in the recent British debate on the manufacture of animal-human hybrid embryos: "only a tiny fraction" of the hybrid made by the Dolly cloning method (nuclear transfer) contains animal DNA. Given that it features in mitochondria, which are central to a range of diseases; given a single spelling mistake in DNA can be catastrophic; and given no-one really understands what nuclear transfer does, this "fact" was propaganda.

Some of the most exotic and prestigious parts of modern science are unfettered by facts. I have recently written about whether our very ability to study the heavens may have shortened the inferred lifetime of the cosmos, whether there are two dimensions of time, even the prospect that time itself could cease to be in billions of years. The field of cosmology is in desperate need of more facts, as highlighted by the aphorisms made at its expense ("There is speculation, pure speculation and cosmology.... cosmologists are often in error, never in doubt')

Scientists have to make judgements about the merits of new facts. Ignoring them in the light of strong intuition is the mark of a great scientist. Take Einstein, for example: when Kaufmann claimed to have experimental facts that refuted special relativity, he stuck to his guns and was proved right. Equally, Einstein's intuition misled him in his last three decades, when he pursued a fruitless quest for a unified field theory that was not helped by his lack of interest in novel facts - the new theoretical ideas, particles and interactions that had emerged at this time.

When it comes to work in progress, in particular, many scientists treat science like a religion - the facts should be made to fit the creed. However, facts are necessary for science but not sufficient. Science is when, in the face of extreme scepticism, enough facts accrue to change lots of minds.

Our rising and now excessive faith in facts alone can be seen in a change in the translation of the motto of the world's oldest academy of science, the Royal Society. Nullius in Verba was once taken as 'on the word of no one' to highlight the extraordinary power that empirical evidence bestowed upon science. The message was that experimental evidence trumped personal authority.

Today the Society talks of the need to 'verify all statements by an appeal to facts determined by experiment'. But whose facts? Was it a well-designed experiment? And are we getting all the relevant facts? The Society should adopt the snappier version that captures its original spirit: 'Take nobody's word for it'.