The HARDtalk programme, like so many others in the churn of 24/7 news tends to focus on people and places facing problems and challenges. More often than not we hold the powerful to account for things that went wrong, not right. Are we missing the bigger picture about the world we live in? Stephen Sackur speaks to the psychologist and writer, Steven Pinker. His new book, Enlightenment Now, is a paean to human progress driven by reason and science. How convincing are his reasons to be cheerful?(Photo: Psychologist and writer Steven Pinker)