Philip Dodd talks to internationally renowned video artist Bill Viola about his latest show: nine major new works in a museum-scale exhibition in London. What is the play, A Satire of the Three Estates relevance to Scottish identity today? We ask Professor Greg Walker who has restored the text, and theatre critic Joyce McMillan. Award-winning documentary maker Norma Percy discusses her latest series on the Iraq war and Jules Evans, one of this year's Radio 3 New Generation Thinkers, reflects on philosophy.