Janna Levin is an astrophysicist and writer. She has contributed to an understanding of black holes, the cosmology of extra dimensions, and gravitational waves in the shape of spacetime. She is the author of “A Madman Dreams of Turing Machines,” which won the PEN/Bingham prize. This interview is edited and produced with music and other features in the On Being episode “Janna Levin — Mathematics, Purpose, and Truth.” Find more at onbeing.org.