A. C. Grayling has written more than thirty books of philosophy, biography, and history of ideas, and judged the Booker Prize—twice. Live from London, he joins Kim Hill to discuss the paradox of knowledge outlined in his new book, The Frontiers of Knowledge: we once thought that enquiry diminishes ignorance, but the opposite is true. Spectacular advances in science, history and psychology have vastly extended our understanding of time, space, and the human brain. Yet each new step simply raises new questions that were previously impossible to ask: the more we know, the greater our ignorance. Erudite and engaging, A. C. Grayling explores just how much we know about the past, the world and ourselves.