In his new book, The Moral Landscape, Sam Harris sets out to convince us that science can not only help us to understand human values, but determine them. Richard Dawkins has said of the book that “moral philosophers will find their world turned upside down”. However, when the book was released in America last year, they argued it was Harris, a Stanford philosophy graduate, who had got things the wrong way up. I got the opportunity to put some of their criticisms to Harris when I met him in Santa Monica, not far from his Los Angeles home.