EXCERPT In his first major book, The Discovery of Dynamics (1989), theoretical physicist and historian of physics Julian Barbour described the process of discovery and progress in science as ‘a journey into the totally unknown, in which shock follows shock’. A decade on, in The End of Time (1999) he put forth in popular form his thesis, developed over some decades, regarding what he had come to believe would be the next great shock to our commonsense picture of the world – namely, that the concept of time would cease to have any role in the foundations of physics. More starkly expressed, Barbour predicts that the next great revolution in our understanding of the universe will entail the realisation that time does not exist—a thesis which, if true, would be shocking indeed. The question, of course, is whether it is true; and, if it is, how we could ever possibly find a way to test and confirm such a seemingly outrageous hypothesis. In our interview with Barbour, we ask him about the motivations which led him to develop his radical position, the paradoxes and problems which arise in trying to make sense of it, and his own eccentric position in relation to mainstream academic theoretical physics…