In a fascinating discussion, historian Simon Schaffer dives into the complexities of the Scientific Revolution. He examines whether it truly revolutionized ideas or just practices, and how it shifted paradigms of authority. Schaffer highlights the role of figures like Galileo and Newton while unpacking the concept of the 'Republic of Letters' and its impact on knowledge sharing. He also addresses the linguistic challenges of communicating scientific ideas, arguing for the need for a universal language like mathematics.

Melvyn Bragg and guests discuss Alan Turing (1912-1954) whose 1936 paper On Computable Numbers effectively founded computer science. Immediately recognised by his peers, his wider reputation has grown as our reliance on computers has grown. He was a leading figure at Bletchley Park in the Second World War, using his ideas for cracking enemy codes, work said to have shortened the war by two years and saved millions of lives. That vital work was still secret when Turing was convicted in 1952 for having a sexual relationship with another man for which he was given oestrogen for a year, or chemically castrated. Turing was to kill himself two years later. The immensity of his contribution to computing was recognised in the 1960s by the creation of the Turing Award, known as the Nobel of computer science, and he is to be the new face on the £50 note.WithLeslie Ann Goldberg Professor of Computer Science and Fellow of St Edmund Hall, University of OxfordSimon Schaffer Professor of the History of Science at the University of Cambridge and Fellow of Darwin CollegeAnd Andrew Hodges Biographer of Turing and Emeritus Fellow of Wadham College, OxfordProducer: Simon Tillotson

Melvyn Bragg and guests discuss the development of photography in the 1830s, when techniques for 'drawing with light' evolved to the stage where, in 1839, both Louis Daguerre and William Henry Fox Talbot made claims for its invention. These followed the development of the camera obscura, and experiments by such as Thomas Wedgwood and Nicéphore Niépce, and led to rapid changes in the 1840s as more people captured images with the daguerreotype and calotype. These new techniques changed the aesthetics of the age and, before long, inspired claims that painting was now dead.WithSimon Schaffer Professor of the History of Science at the University of CambridgeElizabeth Edwards Emeritus Professor of Photographic History at De Montfort UniversityAndAlison Morrison-Low, Research Associate at National Museums ScotlandProducer: Simon Tillotson.