From the BBC Radio 4 series about life's big questions - http://www.bbc.co.uk/historyofideas “I think, therefore I am” This is Descartes' famous Cogito argument: Cogito Ergo Sum. This short animation explains how he came to this conclusion of certainty when surrounded by uncertainty and doubt. Narrated by Stephen Fry. Scripted by Nigel Warburton. This project is from the BBC in partnership with The Open University, the animations were created by Cognitive.