What if all the ideas and values surrounding our lives are like pieces of sediment in a river? Some never quite settle and get swept away, lost to the currents of time. But some take hold, solidify, become part of the cultural bedrock that underpin our lives. With the help of a geologist and a philosopher, Becky Ripley and Emily Knight dig deeper into this metaphor, to unearth the sedimented histories shape our lives. Featuring geologist Chris Jackson, Professor of Basin Analysis at Imperial College London, and philosopher Julian Baginni, author of 'How the World Thinks'. Produced and presented by Emily Knight and Becky Ripley.