Why do 70 per cent of Americans believe in angels, and thousands more that they have been abducted by aliens? Why does every society around the world have a religious tradition of some sort? What makes people believe in things when all the evidence points to the contrary? Why do 13 per cent of British scientists touch wood?

In "Through the Looking Glass", the White Queen tells Alice that to believe in a wildly improbable fact she simply needs to 'draw a long breath and shut your eyes'. Alice finds this advice ridiculous. But don't almost all of us, at some time or another, engage in magical thinking?

Professor Lewis Wolpert investigates the nature of belief and its causes. He looks at belief's psychological basis and its possible evolutionary origins in physical cause and effect. How did toolmaking drive human evolution? Is it the lack of an explanation about fundamental questions which is truly intolerable? Are we born with an evolutionary propensity to believe in things that make us feel better?

Wolpert explores the different types of belief - including that of animals, of children, of the religious, and of those suffering from psychiatric disorders. And he asks whether it is possible to live without belief at all, or whether it is a necessary component of a functioning society.