50 years of Dr Who is celebrated this weekend by the BBC. Matthew Sweet discusses the TV series with historian Dominic Sandbrook, philosopher Ray Monk and New Generation Thinker and cultural historian Fern Riddell. A Free Thinking career interview with artist William Tillyer, whose work is being celebrated in a retrospective at the Middlesbrough Institute of Modern Art MIMA. Dr Adam Smith reflects on the political philosophy underlying the rhetoric of the Gettysburg address, given by Abraham Lincoln 150 years ago.