Andrew Marr talks to the prize-winning novelist, Peter Carey about his latest work, The Chemistry of Tears. At its heart is a small clockwork puzzle and Carey muses on how the industrial revolution has changed what it means to be human. The science writer Philip Ball goes back another century to the world of Galileo and Newton, to study the changes in thinking and knowledge embodied by the scientifically curious. And the historian Rebecca Stott rediscovers the first evolutionists, and the collective daring of Darwin's scientific forebears who had the imagination to speculate on the natural world.

Producer: Katy Hickman.