If you think the Earth is flat, don't worry. It's perfectly natural.
It is not very fashionable to claim that the Earth is flat, or that the sun revolves around it. But such beliefs may be perfectly reasonable, says Professor Lewis Wolpert, of University College London. Reasonable, that is, to those untutored in the scientific method.
After all, common sense suggests that the Earth is indeed flat, the sun most certainly circles the Earth, and a high tide at Calais rules out a simultaneous flood at Hastings.
But science has nothing to do with common sense. Not according to Mr Wolpert, professor of biology as applied to medicine at UCL, and chair of the Committee for the Public Understanding of Science (Copus). Scientific understanding, gleaned from observation, experiment, measurement, is counter-intuitive, he argues. It is difficult. And unless this is recognised, there will always be problems explaining scientific thought to a broader public. Pretending to children that science is either easy or based on common sense is a fundamental mistake.
"Science is a special and different mode of thought," he told the audience at a recent symposium on communicating scientific understanding organised by Jesus College Cambridge. "If an idea fits with common sense then scientifically it's going to be wrong. Science really is peculiar.
"It's because people think that the world works on a common-sense basis that they get so confused about science. If you actually tell them, 'Look it doesn't fit with common sense', they feel much more relaxed about science. This is why Aristotle was so wrong about everything. He thought that the world was built on a common-sense basis. To take the most obvious example: I think it's disingenuous if you say it's obvious that the earth goes round the sun, and not the other way around."
Anyone reaching this conclusion independently would, he argued, need to understand some quite complex physics - in particular the relative behaviour of objects of different mass.
Not only is scientific thought difficult, said Professor Wolpert, it is an historical oddity, having arisen only in ancient Greece; no other civilisation came upon it. Indeed for most of human history, we have got along perfectly well with common sense. It is only recently, for example, that science has affected even such technological enterprises as the building of cathedrals, or the development of machinery.
"Science had zero impact on technology until the 19th century. The steam engine did more for science than science for the steam engine," he told the Cambridge symposium.
Our instinct is to attempt to explain the world in grand terms. Religious belief, metaphor, imagination: these mainstays of our thought are common sense. But science is different, he believes, and we should acknowledge the fact.