Why does every society around the world have a religious tradition of some sort? 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. 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.