From Newton's laws to E=mc2, we think we have uncovered the secrets of the universe. But some claim these laws evolve and others point to their human and cultural origins. Might eternal natural laws be human hubris? Or is the mind of God in our grasp?

A dialogue at the 2015 "How The Light Gets In" Festival, at Hay-on-Wye, with Nancy Cartwright and John Ellis, chaired by Alok Jha. From iai, The Institute of Art and Ideas Philosophy for our times: cutting edge debates and talks from the world's leading thinkers.