Philosopher Adam Smith used the metaphor of an ‘invisible hand’ to describe how individuals making self-interested decisions can collectively and unwittingly engineer an effective economic system that is in the public interest. Narrated by Aidan Turner. Scripted by Nigel Warburton. From the BBC Radio 4 series about life’s big questions – A History of Ideas. This project is from the BBC in partnership with The Open University, the animations were created by Cognitive.