Is it ever morally acceptable to tell a lie? Kant thought not. His example of the would-be murderer explains his reasoning. Read by Harry Shearer. Scripted by Nigel Warburton. From the BBC Radio 4 series - A History of Ideas. http://www.bbc.co.uk/programmes/b04bwydw This project was possible in partnership with The Open University http://www.open.edu/openlearn/historyofideas and the animations were created by Cognitive.